EXPERIMENTAL AND THEORETICAL-STUDIES ON THE DIASTEREOSELECTIVE DIELS-ALDER REACTIONS OF CHIRAL 1-ALKOXY-1,3-BUTADIENES .1. PARENT SYSTEM AND 4-SUBSTITUTED DERIVATIVES

Chiral 1-alkoxy-1,3-dienes (parent and 4-substituted) have been prepar ed from the corresponding chiral alkoxyacetylenes in a stereoselective manner following a 2C + 2C approach. The Diels-Alder reactions of the dienes with maleic anhydride and 4-phenyl-3H-1,2,4-triazoline-3,5-dio ne take place with significant diastereoselectivity. Theoretical calcu lations on these cycloadditions, performed with the SCF-MO procedure A MI, have been used in the stereochemical assignment of the adducts. (C ) 1997 Elsevier Science Ltd.