Silanes, retro-1,5-Brook rearrangement

A regioselective lithiation/retro-Brook rearrangement by direct deprotonation to give benzyl silanes and vinyl silanes has been reported (Scheme 162). ... [Pg.580]

Danheiser used retro-1,2-Brook rearrangement of allyl silyl ethers in a convenient route to a,/ -unsaturated acyl silanes. For example, 2-methyl-2-propen-l-ol was converted to the trimethylsilyl ether and, in a single-pot process, deprotonated by addition of 1.2 equiv terr-butyllithium. Protonation with a solution of acetic acid in tetrahydrofuran gave the of-hydroxyallylsilane 144. Removal of volatiles from the thermally sensitive product provided 95-percent-pure material that was oxidized to the a,P-unsaturated acyl silane 145 under Swem conditions. ... [Pg.429]

An aluminum hydride reduction of propargylic alcohol 153 to trans alkene 156 was found to proceed through retro-1,3-Brook rearrangement to vinyl silane diol 155, followed by 1,3-Brook rearrangement back again. While the final product 156 was isolated directly after longer reaction times, immediate workup following the aqueous ammonia quench revealed the formation of... [Pg.430]

A retro-1,5-Brook rearrangement may have been the source of the unusual silane 173, formed unexpectedly in the course of Evans s studies on phosphonamide-stabilized carbanions. Metalation at the A-methyl position would lead to the rearrangement of 172 across a unique heteroatom-containing tether. ... [Pg.433]

Big Chemical Encyclopedia