Intramolecular methylation of an allyl sulfone via lithium alkoxyaluminate; application to the enantioselective synthesis of the CD ring of vitamin D3.

ABSTRACT

Alcohol-directed intramolecular methylation of an enantiopure allyl sulfone using AlMe(3) provides a trans-hydrindane CD ring alcohol. The substrate cis-CD ring allyl sulfone alcohol is prepared via intramolecular allyl sulfonyl anion addition to aldehyde using Ba(OH)(2).