Trimethylsilylmethyl derivatives carbonylation

Carbonylation of the trimethylsilylmethyl derivatives 5a and 5J> provides further information on the reactivity of organoactin -ide bihaptoacyls (6,33 ). The reaction of these compounds with carbon monoxide takes place at -78° C (equation (12)). 

Similarly, Hosomi and co-workers (15) reported isothioureas as azomethine ylide equivalents. Both A-substituted and A-unsubstituted A-(trimethylsilylmethyl)-isothiourea precursors underwent cycloaddition reactions with carbonyl compounds, when treated with stoichiometric CsF to deliver a range of 2-iminooxazolidine derivatives. Typically, 63 (R = CN, R = H) furnished adduct... 

Annulation /raw-3,4-Disubstituted tetrahydrothiophenes are obtained from conjugated carbonyl compounds and chloromethyl trimethylsilylmethyl sulfide in a reaction mediated by CsF. When the conjugated carbonyl component bears a chiral auxiliary, the process is amenable to synthesis of enantiopure derivatives. 

The anions, generated in situ by desilylation of silylacetylenes, allylsilanes, propargylsilanes, a-silyloxetanones, bis(trimethylsilylmethyl) sulfides, and other silane derivatives,can undergo nucleophilic addition to ketones and aldehydes (eq 11). Al-(C,C-bis(trimethylsilyl)methyl) amido derivatives can add to aldehydes followed by Peterson alkenation to form acyl enamines. Treatment of 2-trimethylsilyl-l,3-dithianes can generate dithianyl anions, which are capable of carbocyclization via direct addition to carbonyl or Michael addition (eq 12). The fluoride-catalyzed Michael additions are more general than Lewis acid-catalyzed reactions and proceed well even for those compounds with enolizable protons and/or severe steric hindrance (eq 13). ... 

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