Regioselectivity in nickel(0) catalyzed cycloadditions of carbon dioxide with diynes

被引：109

作者：

Tekavec, TN ^{[1
]}

Arif, AM ^{[1
]}

Louie, J ^{[1
]}

机构：

[1] Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA

来源：

TETRAHEDRON | 2004年 / 60卷 / 34期

关键词：

nickel; carbon dioxide; N-heterocyclic carbenes; cycloaddition; regioselectivities;

D O I：

10.1016/j.tet.2004.06.025

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The regioselectivity of Ni(0)-catalyzed cycloadditions of CO2 (1 atm) with various asymmetrical diynes to afford pyrones was explored. The use of 1,3-bis-(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) provided high regioselectivity when one terminal substituent on the diyne was a methyl group and the other was medium or large in size (R-L = i-Pr, t-Bu, or TMS). In contrast, the use of a relatively small N-heterocyclic carbene, 1,3-dimesitylimidazol-2-ylidene (IMes), afforded high selectivity only when R-L was large (TMS). X-ray crystal analysis of the major isomer indicated that the relatively large R-L group was in the 3-position of the pyrone. (C) 2004 Elsevier Ltd. All rights reserved.

引用

页码：7431 / 7437

页数：7

共 26 条

[1] DIELS-ALDER CYCLOADDITIONS OF 2-PYRONES AND 2-PYRIDONES [J].