Cyclopropanation of protected chiral, acyclic allylic alcohols: expedient access to the anti-cyclopropylcarbinol derivatives.
The diastereoselective cyclopropanation of silyl-protected chiral allylic alcohols using Shi's carbenoid (TFA-Et(2)Zn-CH(2)I(2)) gave access to the anti-cyclopropylcarbinyl silyl ethers with excellent diastereocontrol. The level of stereocontrol was shown to depend on the sizes of the protective group and the allylic substituent. [reaction: see text]