Reaction of dimethylsilylene with allyl ethers

Abstract

Szammary Dimethylsilylene, generated by photolysis of THE strength of the silicon-oxygen bond1 makes reactions of silylenes with oxygen-containing compounds of particular interest. We report here the first reaction of divalent dodecarnethylcyclohexasilane, reacts with alkyl ally1 ethers to give alkoxyallyldimethylsilanes.

Silylene oxonium ylides: di-tert-butylsilylene insertion into C–O bonds

“…Common oxonium carbene ylide reactions involve [1,2]-Stevens rearrangements1 (Scheme 1) and [2,3]-sigmatropic rearrangements (Scheme 2) to form synthetically useful products 2-11. Analogous oxonium silylene ylides have also been observed 12-15. Allylic ethers subjected to photolytically generated silylenes most often formed silacyclopropane intermediates instead of oxonium ylides 14.…”

Metal-Catalyzed Silylene Insertions of Allylic Ethers: Stereoselective Formation of Chiral Allylic Silanes

“…Stereochemical studies indicate that it should be possible to prepare optically active allylic silanes by insertion into optically active allylic alcohols. Consequently, this transformation may be useful in stereoselective synthesis because chiral allylic silanes are synthetically valuable, but they are challenging to prepare. − …”

“…Consequently, this transformation may be useful in stereoselective synthesis because chiral allylic silanes are synthetically valuable, 17 but they are challenging to prepare. [18][19][20][21][22][23] The insertion of a silylene into an allylic C-O bond was first observed during investigations of silylene transfer to alkenes containing protected hydroxyl groups. 24 Treatment of allylic ether 1 with 2 equiv of cyclohexene silacyclopropane 2 and a catalytic amount of AgO 2 CCF 3 yielded a product where two di-tertbutylsilylene (t-Bu 2 Si) groups were inserted into the allylic C-O bond to form allylic disilane 3 (eq 1).…”

Metal-Catalyzed Rearrangement of Homoallylic Ethers to Silylmethyl Allylic Silanes in the Presence of a Di-tert-butylsilylene Source

“…When silylene transfer was performed at room temperature or above, two di- tert -butylsilylene units were incorporated into the molecule and complete rearrangement of the carbon backbone occurred (Scheme ) . While allylic ethers are known to undergo sigmatropic rearrangements in the presence of silylenes, − rearrangements of homoallylic ethers have not been reported. We felt that this transformation merited further study because silylmethyl allylic silanes have been used in the synthesis of natural products, , but their syntheses have proven to be difficult…”