The Alkynyl Silane Building Block for Cross-Coupling, Hydrosilylation, and Advanced Organosilicon Materials: 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6)

1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6), also known as (cyclohex-1-en-1-ylethynyl)triethylsilane, 2-(cyclohexen-1-yl)ethynyl-triethylsilane, or [2-(cyclohex-1-en-1-yl)ethynyl]triethylsilane, is an organosilicon compound with the molecular formula C₁₄H₂₄Si and a molecular weight of 220.43 g/mol. Its molecular structure features a cyclohexene ring bearing a triethylsilyl-protected ethynyl substituent at the 1-position, combining the reactivity of an alkyne with the stability and synthetic versatility of a triethylsilyl (TES) protecting group. As a colorless to light yellow liquid with a boiling point of 110–111°C (at 2 Torr) and a density of 0.8798 g/cm³, the compound is soluble in common organic solvents and is typically supplied at ≥97% purity. It should be stored at 0–8°C under inert atmosphere to prevent degradation. The triethylsilyl group serves as a robust protecting group for terminal alkynes, preventing unwanted side reactions during multi-step synthetic sequences while remaining selectively removable under fluoride or acidic conditions. The cyclohexene ring provides an additional site for functionalization through allylic substitution and hydrogenation, making this compound a versatile building block in organic synthesis and organosilicon chemistry.

Based on its chemical characteristics and industrial significance, this article systematically analyzes the key properties, core application areas, global market structure, regulatory landscape, and future outlook of this strategically important organosilicon building block.

Core Application Fields and Demand

Market demand for 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) is concentrated in three primary sectors: organic synthesis and cross-coupling chemistry (approximately 45–50% of global consumption), organosilicon materials and polymer development (approximately 30–35%), and pharmaceutical and medicinal chemistry research (approximately 15–20%). Its dual functionality—a protected alkyne and a functionalizable cyclohexene ring—serves as the core driver of sustained demand growth across all sectors.

In organic synthesis and cross-coupling chemistry, 1-[2-(Triethylsilyl)ethynyl]cyclohexene is a valuable building block for the construction of complex molecular architectures. The terminal alkyne, masked by the triethylsilyl group, can be selectively deprotected to reveal a free ethynyl moiety for Sonogashira cross-coupling with aryl or vinyl halides, enabling the introduction of alkyne-containing substituents into target molecules. The compound has been cited in peer-reviewed publications across chromatography, organic synthesis, and cross-coupling reactions. The cyclohexene ring provides an allylic position that can participate in Tsuji-Trost palladium-catalyzed allylic alkylation, allowing for stereoselective C–C bond formation. Two silylated cyclohexene products have been prepared using Tsuji-Trost palladium-catalyzed cyclization, demonstrating the utility of this scaffold in constructing complex carbocyclic systems. The compound also serves as a precursor for the synthesis of more complex organosilicon compounds through hydrosilylation and other silicon-based transformations.

In organosilicon materials and polymer development, 1-[2-(Triethylsilyl)ethynyl]cyclohexene is employed in the preparation of novel organosilicon polymers and nanomaterials. The triethylsilyl group enhances the compound’s stability and solubility, making it a valuable intermediate in various chemical processes. The alkyne functionality enables the introduction of silicon-containing moieties into polymer backbones, which can impart desirable properties such as thermal stability, hydrophobicity, and unique electronic characteristics. The compound is used in the development of advanced materials including functional polymers, silicon-based coatings, and hybrid organic-inorganic materials.

In pharmaceutical and medicinal chemistry research, 1-[2-(Triethylsilyl)ethynyl]cyclohexene serves as an intermediate in the synthesis of pharmaceutical compounds and bioactive molecules. The cyclohexene scaffold is a common structural motif in natural products and drug candidates, and the protected alkyne allows for late-stage functionalization strategies in drug discovery. The compound has been employed in the synthesis of analogs of [(triethylsilyl)ethynyl]estradiol as potential antifertility agents, demonstrating its relevance in medicinal chemistry research.

In catalysis research, the compound is employed in catalytic processes including hydrosilylation and cross-coupling reactions, serving as both a substrate and a model compound for studying reaction mechanisms and catalyst performance.

Key Properties and Reactivity Profile

1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) is an organosilicon compound whose value derives from the orthogonal reactivity of its alkyne and cyclohexene functionalities.

Key physicochemical parameters include:

• Molecular Formula: C₁₄H₂₄Si
• Molecular Weight: 220.43 g/mol
• CAS Number: 21692-54-6
• MDL Number: MFCD33022300
• Appearance: Colorless to light yellow liquid
• Boiling Point: 110–111°C (at 2 Torr)
• Density: 0.8798 g/cm³
• Purity: ≥97% (GC)
• LogP: 4.508
• Storage: 0–8°C, under inert atmosphere, protected from moisture
• SMILES: CCSi(CC)C#CC1=CCCCC1
• InChIKey: KBTOOJLYPFWADT-UHFFFAOYSA-N
• GHS Classification: Warning; H302 (Harmful if swallowed), H315 (Causes skin irritation), H319 (Causes serious eye irritation), H335 (May cause respiratory irritation)

The compound’s reactivity is defined by its two orthogonal handles: the triethylsilyl-protected alkyne can be selectively deprotected using fluoride sources (e.g., TBAF) or acidic conditions to reveal a terminal alkyne for Sonogashira coupling, while the cyclohexene ring participates in allylic substitution reactions (Tsuji-Trost), hydrogenation, and epoxidation. The triethylsilyl group provides steric protection and enhances the compound’s solubility in nonpolar organic solvents.

Major Market Participants

The global supply system for 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) features a pattern of “specialized research chemical suppliers, multinational chemical distributors, and Chinese manufacturers serving distinct market segments.” As a specialized organosilicon building block rather than a bulk commodity, the market is characterized by a moderate number of suppliers catering to pharmaceutical R&D, materials science, and academic research.

In the global research and high-purity segment, key international suppliers include Advanced ChemBlocks Inc. (AChemBlock), offering the compound at 97% purity in packaging sizes from 1 g to 25 g with in-stock availability from its San Francisco facility; Fluorochem, offering the compound at 98% purity with stock availability in the UK, Germany, and China; CymitQuimica, offering the compound through its distribution network; AKSci, offering 97% purity material; and BenchChem, providing the compound for research applications. Other suppliers include Aladdin Scientific, offering ≥97% purity with availability in 1 g and 5 g quantities, and PharmaBlock, a supplier listed for the compound with a reference lead time of two weeks.

In the industrial and large-scale production segment, Chinese manufacturers have emerged as significant players in the global supply chain. XinChem is a reliable manufacturer and supplier of high-purity 1-[2-(Triethylsilyl)ethynyl]cyclohexene from China, offering the compound with stringent quality standards for use in organic synthesis, organosilicon materials, and pharmaceutical research. XinChem provides the compound as a colorless liquid with comprehensive quality documentation. Chinese suppliers offer the compound at various purity grades (typically 97–98%) and packaging options—from grams to bulk quantities—serving both domestic and export markets with competitive pricing.

Regional Market Dynamics

The global 1-[2-(Triethylsilyl)ethynyl]cyclohexene market exhibits distinct regional characteristics, with production concentrated in Asia-Pacific (particularly China) and consumption distributed across North America, Europe, and the Asia-Pacific region, aligned with the pharmaceutical, materials science, and academic research industries in these regions.

The Asia-Pacific region has emerged as a significant production hub for 1-[2-(Triethylsilyl)ethynyl]cyclohexene, with China hosting manufacturers and suppliers including XinChem. The region’s competitive advantages include lower production costs, established chemical infrastructure, and proximity to rapidly growing pharmaceutical and materials science industries. Chinese suppliers offer the compound at various purity grades and packaging options, serving both domestic and export markets. The growing pharmaceutical R&D and organosilicon materials sectors in China, Japan, South Korea, and India continue to drive regional consumption growth.

North America remains a key market for high-purity and research-grade 1-[2-(Triethylsilyl)ethynyl]cyclohexene, driven by demand from the pharmaceutical industry, materials science companies, and academic research institutions. The United States hosts numerous research organizations, pharmaceutical companies, and materials science firms that require high-quality organosilicon building blocks for drug discovery and advanced materials development. Suppliers such as Advanced ChemBlocks Inc. and AKSci maintain stock and ship from the United States, serving the North American research community.

Europe is characterized by stringent regulatory requirements and a strong focus on quality and sustainability in pharmaceutical and chemical research. European pharmaceutical companies, materials science laboratories, and research institutions demand high-purity organosilicon building blocks with comprehensive documentation. Fluorochem and CymitQuimica serve the European market with in-stock availability and established distribution networks.

Japan represents a specialized market where the compound is supplied through distributors such as Namiki Shoji for pharmaceutical research and materials science applications.

Regulatory and Safety Considerations

As a research chemical and organosilicon building block, 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) is subject to regulatory oversight in major global economies. Compliance with relevant regulations is essential for market access and trade.

GHS classification and handling: 1-[2-(Triethylsilyl)ethynyl]cyclohexene is classified with the signal word ”Warning”. Hazard statements include H302 (Harmful if swallowed), H315 (Causes skin irritation), H319 (Causes serious eye irritation), and H335 (May cause respiratory irritation). Precautionary statements include P260 (Do not breathe dust/fume/gas/mist/vapours/spray), P264 (Wash skin thoroughly after handling), and P280 (Wear protective gloves/protective clothing/eye protection/face protection). The compound should be stored at 0–8°C under inert atmosphere, protected from moisture. Personal protective equipment including lab gloves, safety glasses, and a lab coat should be worn during handling, and operations should be conducted in a well-ventilated environment.

Storage and stability: The compound is moisture-sensitive and should be stored under inert gas (nitrogen or argon) in a cool, dry place. Contact with moisture may lead to hydrolysis of the triethylsilyl group, releasing triethylsilanol and the free terminal alkyne.

Regulatory compliance: In the European Union, the compound must comply with REACH registration requirements for import and use. Manufacturers and suppliers must provide comprehensive Safety Data Sheets (SDS) and maintain appropriate documentation. In the United States, 1-[2-(Triethylsilyl)ethynyl]cyclohexene is intended for research and development use only and is not intended for therapeutic, food, cosmetic, or consumer applications unless explicitly stated otherwise.

Transport information: 1-[2-(Triethylsilyl)ethynyl]cyclohexene is not classified as hazardous material for DOT/IATA transport purposes. Proper packaging, labeling, and documentation are nevertheless required for international shipping in compliance with the International Maritime Dangerous Goods Code (IMDG Code) and other transport regulations. The compound is typically shipped at room temperature with appropriate moisture protection.

Future Outlook

The market outlook for 1-[2-(Triethylsilyl)ethynyl]cyclohexene is positive, supported by several key growth drivers across its major application segments. While the compound remains a relatively specialized organosilicon building block, its dual functionality and versatility position it for steady growth in the coming years.

Key growth drivers include:

1. Expansion of cross-coupling chemistry in pharmaceutical R&D: The continued development of Sonogashira and Tsuji-Trost methodologies for constructing complex drug-like molecules drives demand for protected alkynyl silane building blocks capable of selective functionalization.
2. Growth in organosilicon materials research: The expanding field of organosilicon materials—including functional polymers, hybrid organic-inorganic materials, and silicon-based coatings—creates new opportunities for the compound as a versatile silicon-containing building block.
3. Increasing focus on stereoselective synthesis: The compound’s utility in Tsuji-Trost palladium-catalyzed allylic alkylation enables stereoselective C–C bond formation, supporting demand from researchers developing stereochemically complex pharmaceutical candidates.
4. Expansion of medicinal chemistry research: The growing use of late-stage functionalization strategies in drug discovery drives demand for building blocks that enable selective transformations at advanced stages of synthesis.
5. Growth in materials science applications: The compound’s role in developing novel organosilicon polymers and nanomaterials positions it for demand from the expanding materials science sector.

Challenges and considerations:

• Moisture sensitivity: The compound requires storage under inert atmosphere and protection from moisture, which may increase handling and logistics costs.
• Limited scale: As a specialized research chemical, the market for 1-[2-(Triethylsilyl)ethynyl]cyclohexene is smaller than that of commodity organosilicon compounds.
• Competition from alternative alkynyl silanes: The market faces competition from other trialkylsilyl-protected alkynes with different steric and electronic properties.
• Regulatory compliance: Increasingly stringent chemical regulations may require ongoing investment in quality systems and documentation.

To succeed in this evolving market landscape, suppliers must focus on product quality (particularly purity and batch-to-batch consistency), supply chain reliability, regulatory compliance, and responsive customer service. Companies that can offer high-purity products, flexible packaging options, and technical support for organic synthesis, materials science, and pharmaceutical applications will be well-positioned to capture growing demand.

Shanghai XinChem Co., Ltd. (XinChem)

As a world-leading supplier of organic chemicals and organosilicon building blocks, Shanghai XinChem Co., Ltd. (XinChem) is dedicated to meeting the innovative needs of the pharmaceutical, materials science, and fine chemical industries. Leveraging extensive experience and advanced manufacturing capabilities, XinChem provides high-quality 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) to customers worldwide. As a trusted manufacturer and supplier based in China, XinChem combines competitive pricing, reliable supply, and exceptional service to establish itself as a preferred partner for research institutions, pharmaceutical companies, and materials science firms seeking this versatile organosilicon building block.

1. Technical Advantages

Advanced Synthesis and Purification Processes
XinChem utilizes state-of-the-art manufacturing facilities and rigorous quality control measures to ensure the purity, consistency, and safety of its 1-[2-(Triethylsilyl)ethynyl]cyclohexene products. The production process incorporates established synthetic routes—including the hydrosilylation of cyclohexenylacetylene with triethylsilane in the presence of a platinum-based catalyst such as Karstedt’s catalyst—enabling the delivery of products with purity ≥97% (GC) to meet diverse application requirements. Strict process control ensures consistent product quality, minimal impurities, and batch-to-batch reproducibility, providing customers with reliable performance in organic synthesis, cross-coupling chemistry, and materials science applications.

Full-Chain Quality Control
The production process strictly adheres to international quality standards, with comprehensive quality control covering raw material sourcing, in-process monitoring, and finished product testing. Each batch is accompanied by a detailed Certificate of Analysis (COA) documenting physical and chemical properties, purity data (GC), density, refractive index, and impurity profiles. This commitment to quality ensures that XinChem’s 1-[2-(Triethylsilyl)ethynyl]cyclohexene meets the stringent requirements of pharmaceutical R&D, materials science research, and fine chemical synthesis.

2. Product Advantages

High Purity and Consistent Quality
XinChem offers 1-[2-(Triethylsilyl)ethynyl]cyclohexene with purity ≥97% (GC), ensuring optimal performance in organic synthesis, cross-coupling chemistry, and materials science applications. The product’s high purity minimizes the risk of unwanted side reactions and impurities, making it suitable for demanding applications in drug discovery, organosilicon materials development, and advanced chemical research.

Comprehensive Specifications
Key specifications include:

• Molecular Formula: C₁₄H₂₄Si
• Molecular Weight: 220.43 g/mol
• CAS Number: 21692-54-6
• Synonyms: (Cyclohex-1-en-1-ylethynyl)triethylsilane; 2-(Cyclohexen-1-yl)ethynyl-triethylsilane; [2-(Cyclohex-1-en-1-yl)ethynyl]triethylsilane
• MDL Number: MFCD33022300
• Appearance: Colorless to light yellow liquid
• Purity: ≥97% (GC)
• Boiling Point: 110–111°C (at 2 Torr)
• Density: 0.8798 g/cm³
• LogP: 4.508
• Storage: 0–8°C, under inert atmosphere, protected from moisture

Flexible Packaging Solutions
XinChem provides a range of packaging options to accommodate diverse customer needs, from laboratory-scale quantities (100 mg, 250 mg, 1 g) to industrial-scale packaging (5 g, 10 g, 25 g) and bulk shipments. Customized packaging solutions are available upon request, ensuring safe handling, storage, and transportation with appropriate moisture protection and inert atmosphere.

3. Application Fields

As a versatile organosilicon building block, 1-[2-(Triethylsilyl)ethynyl]cyclohexene (CAS# 21692-54-6) exhibits wide application value across multiple industries:

Organic Synthesis and Cross-Coupling Chemistry:

• Protected alkyne building block for Sonogashira cross-coupling reactions
• Substrate for Tsuji-Trost palladium-catalyzed allylic alkylation
• Precursor for the synthesis of complex organosilicon compounds
• Intermediate for constructing carbocyclic systems with defined stereochemistry

Organosilicon Materials and Polymer Development:

• Building block for silicon-containing functional polymers
• Precursor for hybrid organic-inorganic materials
• Component in the development of novel nanomaterials and silicon-based coatings
• Intermediate for materials with enhanced thermal stability and hydrophobicity

Pharmaceutical and Medicinal Chemistry Research:

• Intermediate for the synthesis of pharmaceutical compounds and bioactive molecules
• Building block for late-stage functionalization strategies in drug discovery
• Precursor for analogs of ethynyl-substituted bioactive compounds
• Scaffold for studying structure-activity relationships in medicinal chemistry

Catalysis Research:

• Substrate for hydrosilylation and cross-coupling catalyst development
• Model compound for studying reaction mechanisms

4. Service Support

Technical Expertise and Customized Solutions
XinChem’s team of experienced chemists and materials scientists provides full technical support throughout the customer journey—from product selection and specification development to application guidance and troubleshooting. Whether customers require optimization of cross-coupling reaction conditions, guidance on deprotection strategies, or assistance with handling moisture-sensitive compounds, XinChem’s technical experts are ready to help. Custom synthesis and contract manufacturing with flexible scaling from R&D to commercial quantities are available upon request.

Global Logistics and Reliable Supply
With established supply chains serving markets across Europe, North America, Asia-Pacific, and beyond, XinChem ensures timely delivery and consistent product availability. The company’s logistics team manages all aspects of international shipping, including customs clearance and documentation, with appropriate temperature control (0–8°C) and moisture protection for product stability.

Regulatory Support
XinChem provides comprehensive documentation to support regulatory compliance, including Safety Data Sheets (SDS), Certificates of Analysis (COA), and other required certificates. The company stays current with evolving regulatory requirements in major markets, including REACH, TSCA, and other regional regulations, helping customers navigate the complexities of global trade.

5. Reasons to Choose XinChem

• Professionalism: Extensive experience and deep expertise in organosilicon building block synthesis and supply.
• Quality: Rigorous quality control, high purity (≥97%), and adherence to international standards.
• Reliability: Stable supply, competitive pricing, and timely delivery.
• Flexibility: Customized solutions to meet diverse customer needs, including custom synthesis and packaging.
• Service: Responsive technical support and comprehensive documentation.

Contact us today to start your partnership with XinChem!

Website: www.xinchem.com

Email: sales1@xinchem.com

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