Homochiral ketals in organic synthesis. Diastereoselective cyclopropanation of medium and large ring .alpha.,.beta.-unsaturated ketals derived from 1,4-Di-O-benzyl-L-threitol
Homochiral ketals in organic synthesis. Diastereoselective cyclopropanation of medium and large ring .alpha.,.beta.-unsaturated ketals derived from 1,4-Di-O-benzyl-L-threitol