Stereochemistry of the [2+2] Cycloaddition of Chlorosulfonyl Isocyanate to Chiral Alkoxyallenes Derived from 1,3-Alkylidene-L-erythritol and -D-threitol
The [2+2] cycloaddition of chlorosulfonylisocyanate to alkoxyallenesderivedfrom ethylidene and benzylidene erythritols and threitols proceeds with a moderate asymmetric induction in the case of the erythritols and with a very low induction in the case of threitols. This indicates that the erythritol derivatives may exist in solution in one predominant conformation while the threitol derivatives