Pseudoguaianolides from intramolecular cycloadditions of aryl diazoketones: synthesis of (±)-confertin and an approach to the synthesis of (±)-damsin

Abstract

Rhodium (II) mandelate-catalysed cyclisation of α-diazoketones derived from 3-arylpropionic acids produces bicyclo[5.3.0]decatrienones, one of which has been used to synthesise an advanced (±)confertin intermediate in six stages and 20% overall yield. The possibility of constructing intermediates for the synthesis of damsin-like pseudoguaianolides via catalysed diazoketone cyclisation is also examined and methods for the construction of polyfunctional 3-arylpropionic acids suitable for use as damsin precursors are presented.