Indium- and zinc-mediated allylation of difluoroacetyltrialkylsilanes in aqueous media

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

“…Metal-mediated allylation of difluoroacetyltrialkylsilanes with various allyl bromides in aqueous media formed homoallylic alcohols exclusively. The common Brook rearrangement, carbon to oxygen-silyl migration, was totally suppressed with no detectable formation of silyl enol ether . The reaction afforded high syn selectivity regardless of the allylic bromide geometry.…”

“…The common Brook rearrangement, carbon to oxygen-silyl migration, was totally suppressed with no detectable formation of silyl enol ether. 322 The reaction afforded high syn selectivity regardless of the allylic bromide geometry. The enantioselective indium-mediated allylation was attempted and found to give the desired products in moderate yields with high syn selectivity and enantioselectivity.…”

Recent Advances in Indium-Promoted Organic Reactions

“…27 Whereas the allylation of the fluorinated acylsilanes 1 with Grignard reagents was followed by Brook rearrangement and consecutive defluorination, such side-reactions were avoided in the aqueous indium-mediated synthesis of the fluorinated alcohols 2 (Scheme 2). 28 Hemiacetals, as masked aldehydes, have been shown to undergo indium-mediated allylation; this was recently exploited in the aqueous allylation of unprotected sugars or dihydrofurans after their indium(III)-catalyzed hydrolysis into lactols. 29 Compared to other metals, indium was particularly efficient in the promotion of the allylation of fluoral methyl hemiacetal, leading to a-trifluoromethylated homoallylic alcohols in water or N,N-dimethylformamide.…”

Heterogeneous Rate Constants for Indium Mediated Allylations: Cinnamyl Chloride in Ethanol/Water Mixtures

“…The mechanism has been demonstrated to proceed by way of an organoindium intermediate. As illustrated in Scheme , the rate limiting step , is the heterogeneous reaction of the allyl halide on solid indium metal to generate an allyl indium intermediate (vide infra). − The intermediate then goes on to couple with a wide range of electrophiles, often by way of a chelated transition state. − The nature of the solvent exerts unusually high influence on the outcome of the reaction, including the nature of the product, the yield, and the rate. ,− Studies have identified at least five steps where solvent can influence the outcome of IMAs.…”