Chromium(II) chloride-mediated coupling reactions of Garner aldehyde with allyl bromides: facile asymmetric synthesis of (2R,3S)-3-hydroxy-2-hydroxymethylpyrrolidine

Abstract

Chromium(II) chloride-mediated coupling reactions of 1,1-dimethylethyl (S)- and (R)-4-formyl-2,2-dimethyloxazolidine-3-carboxylates [(S)- and (R)-Garner aldehydes ] (1a,b) with allyl bromides 2a–c proceeded with moderate to good stereoselectivity to give the corresponding homoallyl alcohols 3a–d in good yields. The homoallyl alcohol 3b was easily transformed to (2R,3S)-3-hydroxy-2-hydroxymethylpyrrolidine 8.