Intramolecular [2 + 2] Cycloaddition Reactions of Alkynyl Ether Derived Ketenes. A Convenient Synthesis of Donor–Acceptor Cyclobutanes
作者:Vincent Tran、Thomas G. Minehan
DOI:10.1021/ol202989c
日期:2011.12.16
of tert-butyl alkynylethers 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