SmI2-mediated tandem cyclization route for stereoselective synthesis of the tetracyclic core of daphenylline.

A unique strategy involving SmI2-mediated tandem cyclization reaction of suitably substituted dialdehyde embedded with an α,β-unsaturated ester for the synthesis of the structural core of the complex alkaloid daphenylline is presented. This strategy involves the formation of two C-C bonds and a C-O bond in the form of a lactone in a single simultaneous operation.