Diels-Alder reactions of 4-alkenylthiazoles:: A new approach to thiazole functionalization

被引:14
作者
Alajarin, Mateo
Cabrera, Jose
Pastor, Aurelia
Sanchez-Andrada, Pilar
Bautista, Delia
机构
[1] Univ Murcia, Dept Quim Organ, Fac Quim, E-30100 Murcia, Spain
[2] Univ Murcia, Serv Instrument Cientif, E-30100 Murcia, Spain
关键词
D O I
10.1021/jo062417e
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Somewhat unexpectedly, the computed highest occupied molecular orbital (HOMO) energies of some 4-alkenylthiazoles afforded values close to those calculated for the Danishefsky-Kitahara and Rawal dienes. In fact, 4-alkenylthiazoles behave as all-carbon dienes in Diels-Alder reactions with the participation of the formal C-C double bond of the thiazole ring and the side-chain double bond. The reactions with N-substituted maleimides, maleic anhydride, and naphthoquinone take place with high levels of stereocontrol to give the corresponding endo-cycloadducts in good to excellent yields. Depending on the dienophile, the cycloadduct further transforms under the reaction conditions through either a 1,3-hydrogen shift, dehydrogenation, or an ene reaction or Michael addition with another molecule of dienophile. These unprecedented results open new synthetic perspectives for the functionalization of the thiazole ring.
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页码:2097 / 2105
页数:9
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