Synthesis of Optically Active cis- and trans-1,2-Disubstituted Cyclopropane Derivatives by the Simmons-Smith Reaction of Allyl Alcohol Derivatives Derived from (R)-2,3-O-Isopropylideneglyceraldehyde

Article abstract of DOI:10.1021/jo00080a017

The Simmons-Smith reactions of Z- and E-allyl alcohol derivatives 6 derived from (R)-2,3-O-isopropylideneglyceraldehyde (5) were used for the synthesis of optically active cis- and trans-1,2-disubstituted cyclopropane derivatives.Reaction of 6 with diethyl zinc and diiodomethane gave cyclopropane derivatives 7 in 84percent to quantitative yields with 35 to ca. 100percent des.Identical facial selectivities toward the double bonds, 1re-2si for Z-6 and 1re-2re for E-6, were observed in the cyclopropanations.The diastereoselectivity was dependent on the protecting group on the terminal allylic oxygen (R of 6, TBDPS > MOM > Bn) and on the stereochemistry of the double bond (Z > E).For TBDPS ethers Z- and E-6c, cis- and trans-7c were obtained as single diastereomers, respectively.It was clearly demonstrated that the stereoselectivity of the cyclopropanation is controlled by the directing effect of the allylic oxygen (O-1) of the dioxolane ring, which coordinates to the reagent.The terminal allylic oxygen (O-2) lowered the diastereoselectivity.This reaction was applied to the synthesis of optically active cyclopropane analogs of γ-aminobutyric acid (GABA) 18, 22, and ent-22.