Stereoselective Synthesis of Dialkyl-1,1-diacetyl-8ahydroxy- 8-oxo-1,2,8,8a-tetrahydrocyclopenta[ a]indene-2,3-dicarboxylates

Abstract

Protonation of the highly reactive 1:1 intermediates produced in the reaction between tributylphosphine and dialkyl acetylenedicarboxylates by acetylacetone leads to sterically congested phosphorus ylides. Reaction between the sterically congested phosphorus ylides with ninhydrin leads to stereoselective synthesis of dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-1,2,8,8a-tetrahydrocyclopenta[a]indene-2,3-carboxylates in the presence of magnesium hydrogen sulfate powder in solvent-free conditions under microwave (1 KW, 3 min) and thermal (60ºC, 60 min) conditions.