INTRAMOLECULAR HYDROSILYLATIONS II: THE ANTI-SELECTIVE REDUCTION OF β-HYDROXYKETONES

Article abstract of DOI:10.1016/S0040-4020(01)86634-5

A study was made of the synthesis and intramolecular hydrosilylation of silyloxyketones (2) (Sheme 2).It was found that with a variety of Lewis acid catalysts, anti-selective hydrosilylation took place to give (3) and, after desilylation, (5).With SnCl4, the most effective and practical catalyst, ratios (3):(4) ranged between 40:1 and 120:1 for a number of substrates.An explanation for the stereoselectivity is proposed based on (Cl) as a transition state model.The result is an anti-selective reduction of β-hydroxyketones, summarised in Scheme 4.