79256-94-3Relevant articles and documents
Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group
Fleming, Ian,Patel, Shailesh K.,Urch, Christopher J.
, p. 115 - 124 (2007/10/02)
γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.
Some uses of silicon compounds in organic synthesis
Fleming, Ian
, p. 7 - 13 (2007/10/02)
1.The amount of γ-phenylthioalkylation of silyl dienol ethers is increased when the triphenylsilyl ether is used in place of the trimethylsilyl ether.Phenylthiomethylation is the least γ-selective carbon electrophile of several tried so far. 2.The acid-catalysed reactions of a range of γ-silyl tertiary alcohols cleanly give rearrangement, in which the silyl group controls the outcome.The reactions are similar in several respects to the rearrangements of the corresponding pinacols, except that the silicon controlled reactions are usually cleaner and give higher yields.The reaction is particularly useful for setting up quaternary carbon atoms.
