Acetophenones chirally modified lithium aluminum hydride

The enantioselective reduction of unsymmetrical ketones to produce optically active secondary alcohols has been one of the most vibrant topics in organic synthesis.8 Perhaps Tatchell et al. were first (in 1964) to employ lithium aluminum hydride to achieve the asymmetric reduction of ketones9 (Scheme 4.IV). When pinacolone and acetophenone were treated with the chiral lithium alkoxyaluminum hydride reagent 3, generated from 1.2 equivalents of 1,2-0-cyclohexylidene-D-glucofuranose and 1 equivalent of LiAlHzt, the alcohol 4 was obtained in 5 and 14% ee, respectively. Tatchell improved the enantios-electivity in the reduction of acetophenone to 70% ee with an ethanol-modified lithium aluminum hydride-sugar complex.10... 

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