Bis triisopropylsilyl propyne

More practically, 2-pyridyl-substituted vinylsilanes themselves can be directly subjected to the reactions with various electrophiles. For example, treatment of 2-pyridyl-substituted vinylsilanes with acid chlorides in the presence of aluminum chloride affords the corresponding a, 0-unsaturated enones (eq 5). The reaction of 2-pyridyl-substituted vinylsilanes with bromine and subsequent treatment with sodium methoxide affords the corresponding vinyl bromides (eq 6).  

Physical Data bp 130-135 °C/0.08 mmHg d 0.846 gcm . Solubility both the reagent and its lithio derivative are soluble in ether or THF. 

Analysis of Reagent Purity GC at 210 °C on a glass capillary column coated with OV-17 TLC on silica (hexanes, R( 

A list of General Abbreviations appears on the front Endpapers 

Preparative Method l,3-bis(TIPS)propyne is prepared in quantitative yield by silylation of 3-lithio-l-triisopropylsilyl-l-propyne with triisopropylsilyl trifluoromethanesulfonate.  

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One of the key steps involved in the total synthesis of the marine natural product (+)-brasilenyne is a Peterson olefination to introduce the (Z)-enyne side chain (eq 65). BuLi treatment gives the lithiated l,3-bis(triisopropylsilyl)propyne, which is treated with the aldehyde to afford the desired enyne with a 6 1 (Z E) ratio. 

Alkynyltriisopropylsilanes. The acidic alkynic H can be protected with TIPS triflate. Silylation of 1-lithiopropyne with 1 equiv of TIPS triflate in ether at —40 to 0 °C gives an 87% yield of 1-TIPS-propyne (eq 4). l,3-Bis(triisopropylsilyl)propyne, derived from treatment of 1-TIPS-propyne with butyllithium in THF at —20 °C for 15 min followed by TIPS triflate at —78 to —40°C (eq 5), is lithiated with n-BuLi in THF at —20°C for 15 min and then allowed to react with aldehydes (eq 6). The cjs enynes are isolated in high yields. TlPS-propargylmag-nesium bromide together with copper(I) iodide has been used in the displacement of the mesylate derivative of farnesol. ... 

The main use of the title reagent is as a precursor of the lithium derivative. l,3-Bis(triisopropylsilyl)propyne is cleanly lithiated by treatment with 1 equiv of n-butyllithium in THF at —20°C (15 min) to what is probably an equilibrium mixture of propargylic and allenic species (1) and (2) (eq 1). The bulky triisopropylsilyl (TIPS) group serves as a controlling group in the addition of (1/2) to electrophiles. 

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