Tandem [5 + 1]/[8 + 2] cycloaddition reactions involving phosphiranes and tropones: facile access to 6,5,7-fused tricyclic skeletons†
Abstract
Tandem [5 + 1] carbonyl cyclization/[8 + 2] cycloaddition reactions of tropones and phosphiranes were developed as a straightforward synthetic method to synthesize structurally complex 6,5,7-fused tricyclic scaffolds. This one-pot reaction has excellent regio- and periselectivity. The P–O bond was formed exclusively. The highly reactive CP bond enabled the high-order [8 + 2] cycloaddition of tropones.