Diastereoselective addition of lower order vinylcuprates to (R)-2,3-O-isopropylideneglyceraldehyde

Article abstract of DOI:10.1016/S0040-4020(01)81551-9

Highly syn or anti selective addition of lower order lithium vinylcuprates generated from alkenyl bromides 1 to (R)-2,3-O-isopropylideneglyceraldehyde (2) can be achieved, respectively, depending on the substitution pattern of the vinyl moiety and the solvent. α-Trimethylsilyl substituted vinylcuprates possessing an alkyl substituent Z to copper react with excellent syn selectivity in ether whereas a highly anti selective addition is observed for cuprates bearing a hydrogen atom Z or α to the metal in THF. A model is proposed to rationalize these complementary selectivities.