Total synthesis of the clavicipitic acids by anintramolecular azide cycloaddition strategy

A straightforward total synthesis approach to the structurally unique ergot derailment products, the clavicipitic acids 1 and 2, is described. The synthetic strategy is based on the formation of the seven-membered nitrogen-containing ring of 1 and 2through an intramolecular azide cycloaddition process. The cycloaddition strategy, which produces solely the imine product 24, does in some sense mimic the proposed biosynthetic pathway to these acids.