X=Y-ZH systems as potential 1,3-dipoles. Part 34. generation of nitrones from oximes. Tandem michael addition-1,3-dipolar cycloaddition reactions. class 2 processes utilising bifunctional michael acceptor-dipolarophile components.
作者:Ronald Grigg、Michael J. Dorrity、Frances Heaney、John F. Malone、Shuleewan Rajviroongit、Visuvanathar Sridharan、Sivagnanasundram Surendrakumar
DOI:10.1016/s0040-4020(01)91022-1
日期:1991.9
Aldoximes and ketoximes react with a range of bifunctional Michael acceptor-dipolarophile substrates comprising functionalised 1,3-, 1,4- and 1,5-dienes via a tandem process involving an N-alkenyl nitrone intermediate. The 1,3-dienes react regio- and stereo-specifically to give 1-aza-7-oxabicyclo[2.2.1]heptanes whilst sterically unencumbered aryl aldoximes and 1,4-dienes give 1-aza-2-oxabicyclo[3.2
醛酮肟和酮肟通过涉及N-烯基硝酮中间体的串联过程与一系列包含官能化的1,3-,1,4-和1,5-二烯的双官能Michael受体-双极性亲和底物反应。1,3-二烯在区域和立体上发生特异性反应,生成1-氮杂-7-氧杂双环[2.2.1]庚烷,而空间上不受阻碍的芳基醛肟和1,4-二烯生成1-氮杂-2-氧杂双环[3.2]。 1]辛烷衍生物。1-Aza-2-oxa-和1-aza-8-oxa-双环[3.2.1]辛烷的酮肟和1.4消旋混合物。1,5-二烯和酮肟与区域和立体特异性反应,生成1-aza-8-氧杂双环[3.2.1]辛烷衍生物,而苯甲醛肟则生成1:1异构体的1-aza-8-氧杂双环[3.2]混合物。 1]辛烷以及两个差向异构的1-氮杂-2-氧杂双环[3.2.1]辛烷。串联过程的区域和立体化学结果受双功能底物中连接链的长度和性质以及在过渡状态下肟和双极性亲核体上取代基之间的空间相互作用所控制。据报道1-氮杂-7-氧杂双环[2