1,3-Dipolar Cycloadditions of alpha-Diazo Ketones Derived from N-Protected (S)-Proline with Aromatic and Cycloaliphatic Thioketones

Abstract

Enantiomerically pure alpha-oxo diazo compounds derived from (S)-proline were used for 1,3-dipolar cycloaddition with aryl and hetaryl thioketones, as well as with cycloalkanethiones. Whereas the reactions with hetaryl thioketones in boiling THF yield alpha,beta-unsaturated ketones via a cascade of cycloaddition, 1,3-dipolar electrocyclization, and desulfurization, the analogous reactions with thiobenzophenone and cycloalkanethiones result in the formation of 1,3-oxathiole derivatives. In the latter case, the 1,5-dipolar electrocycliz Show more