The Simmons-Smith cyclopropanation of olefins is arguably the most important application of organozinc reagents in organic synthesis. I The reaction proceeds under mild conditions2 and is characterized by broad generality, olefin stereospecificity,'v2 and a high degree of relative stereoselectivity [with allylic alcohols s ether^),^^ acetals, 6 and enol ethers']. Indeed, the strong directing effect of hydroxyl groups was recognized early on3 and has ...
