Chromium(II)-Mediated Stereodivergent Additions of Allylic Phosphates and Halides to Aldehydes

Article abstract of DOI:10.1021/jo00114a026

The addition of γ-disubstituted allylchromium(III) reagents to aldehydes proceeds in a stereodivergent manner, in contrast to the case of γ-monosubstituted allylchromium(III) species.The method allows the preparation of a variety of homoallylic alcohols bearing a quaternary center of defined relative configuration in the α-position.The preparation of both stereomeric homoallylic alcohols 13 is possible by using either of the two (E)- or (Z)-allylic precursors.The reaction has been extended to a γ-monosubstituted β-(trimethylsilyl)allylic system.The intermediate allylic chromium(III) reagents can be conveniently prepared from the corresponding phosphates (or chlorides) in DMPU or THF in the presence of catalytic amounts of LiI.