Gold(I)/Copper(II)-Cocatalyzed Tandem Cyclization/Semipinacol Reaction: Construction of 6-Aza/Oxa-Spiro[4.5]decane Skeletons and Formal Synthesis of (+/-)-Halichlorine

A simple and efficient strategy for the construction of 6-aza/oxa-spiro[4.5]decane skeletons under the cocatalysis of gold( I)/copper(II) was developed, and its potential utility was demonstrated by a formal synthesis of the biologically active marine alkaloid (+/-)-halichlorine.