Department of Chemistry, Colby College, Waterville, Maine 04901, USA.
J Org Chem. 2011 Mar 18;76(6):1584-91. doi: 10.1021/jo1020536. Epub 2011 Feb 22.
The rearrangement of 2-ethoxyethylidene, generated photochemically from a nonnitrogenous precursor, leads to ethyl vinyl ether. Although this product could result, in principle, from a 1,2-hydrogen shift and/or a 1,2-ethoxy shift in the carbene, a deuterium labeling study indicates an essentially exclusive preference for hydrogen migration. The experimental results are in agreement with CCSD and W1BD calculations for the simpler 2-methoxyethylidene system that show a prohibitively large barrier for the methoxy shift and a negligible barrier for the hydride shift.
2-乙氧基亚甲基经光化学重排生成，由非含氮前体制得，生成乙基乙烯基醚。虽然此产物原则上可以通过卡宾的 1,2-氢迁移和/或 1,2-乙氧基迁移生成，但氘标记研究表明其几乎完全优先发生氢迁移。实验结果与对简单的 2-甲氧基卡宾体系的 CCSD 和 W1BD 计算结果一致，表明甲氧基迁移的势垒非常高，而氢迁移的势垒可以忽略不计。
