-.gamma.-lycorane by the intramolecular cycloaddition of an azide with an .omega.chloroalkene 11 was treated with 1-ethoxy-1-[(tert-butyldimethylsilyl)oxy]ethene and lithium perchlorate in ether to produce the gamma,delta-unsaturated ester 12. An... WH Pearson,JM Schkeryantz - 《Acta ...