A novel α-hydroxydihydrochalcone from the heartwood of Pterocarpus angolensis D.C.: absolute configuration, synthesis, photochemical transformations, and conversion into α-methyldeoxybenzoins

Abstract

The absolute configuration of (αR)-α,2′-dihydroxy-4,4′-dimethoxydihydrochalcone from the heartwood of Pterocarpus angolensis D.C. is established. Its structure is substantiated by synthesis and by photochemical conversion of its α-O-tosyl derivative into an α-tosyloxymethyldeoxybenzoin and hence to the α-methyldeoxybenzoin analogue. The photochemical step also leads, amongst others, to α-hydroxymethyldeoxybenzoin, β-hydroxydihydrochalcone, and 2-benzylbenzofuran-3-one analogues depending on the conditions of the photolysis.