烯反应对于烯炔-联烯的C(2)-C(6)环化反应的重要性。

The importance of the ene reaction for the C(2)-C(6) cyclization of enyne-allenes.

作者信息

Musch P W, Engels B

机构信息

Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.

出版信息

J Am Chem Soc. 2001 Jun 13;123(23):5557-62. doi: 10.1021/ja010346p.

DOI:10.1021/ja010346p

PMID:11389639

Abstract

The present study establishes the ene reaction as a competing reaction mechanism to the diradical mechanism for the thermal C(2)-C(6) cyclization of enyne-allenes which possess bulky substituents at the alkyne terminus. Both reaction routes are found to possess nearly equal free energies of activation. As shown by our computations, primary H/D isotope effects could be used for a definite decision about the mechanism. Concerning the regioselectivity of the cyclization reactions of enyne-allenes our study resolves a long-standing deviation between theoretical results and experimental findings.

摘要

本研究确定了烯反应是炔丙二烯热 C(2)-C(6) 环化反应的一种竞争反应机制，该炔丙二烯在炔烃末端具有庞大的取代基。发现这两种反应途径具有几乎相等的活化自由能。正如我们的计算所示，一级 H/D 同位素效应可用于明确确定反应机制。关于炔丙二烯环化反应的区域选择性，我们的研究解决了理论结果与实验发现之间长期存在的偏差。