Synthesis of the Tetracyclic Core of the Tetrapetalones through Transannular Oxidative [4+3] Cyclization

A convergent strategy involving a base-mediated silyl transfer/acylation for fragment coupling and a tandem process consisting of nitro reduction and acyl transfer can be employed to construct strained, bicyclic macrolactams (see scheme). The tetracyclic core of the tetrapetalones, which are effective lipoxygenase inhibitors, can be prepared by using an IIII-promoted cyclization.