Intramolecular [2+ 2] Cycloaddition Reactions of Alkynyl Ether Derived Ketenes. A Convenient Synthesis of Donor–Acceptor Cyclobutanes

V Tran, TG Minehan

Index: Tran, Vincent; Minehan, Thomas G. Organic Letters, 2011 , vol. 13, # 24 p. 6588 - 6591

Full Text: HTML

Citation Number: 16

Abstract

Mild thermolysis of tert-butyl alkynyl ethers furnishes aldoketenes, which undergo facile [2+ 2] cycloaddition reactions with pendant di-and trisubstituted alkenes. A wide variety of cis- fused cyclobutanones are produced in moderate to high diastereoselectivity and good to excellent yields by this method, and free hydroxyl groups are tolerated in the ene-ynol ether starting materials. Enol-ynol ethers also undergo efficient reaction to produce donor– ...