Electrochemical and yeast-catalysed ring-opening of isoxazoles in the synthesis of analogues of the herbicide Grasp ®
作者:Christopher J. Easton、Graham A. Heath、C. Merrîcc M. Hughes、Connie K. Y. Lee、G. Paul Savage、Gregory W. Simpson、Edward R. T. Tiekink、George J. Vuckovic、Richard D. Webster
DOI:10.1039/b008081k
日期:——
Isoxazoles substituted with an electron-withdrawing group at the 4-position undergo electrochemical and yeast-catalysed N–O bond cleavage. The electrolysis is much more efficient and, with acyl- and alkoxycarbonyl-substituted isoxazoles, it affords the enolised dicarbonylimine functionality characteristic of the herbicide Grasp®. Regioisomeric 4- and 5-substituted isoxazoles are accessible through nitrile oxide cycloaddition chemistry, using halogen as a steric auxiliary to control the regiochemistry of reaction. Crystal data for compounds 11 and 19b are presented.
4位带有吸电子基团的异恶唑在电化学和酵母催化下发生N–O键断裂。电解过程更为高效,并且对于酰基和烷氧羰基取代的异恶唑,它能生成草剂Grasp®所特有的烯醇化双羰基亚胺结构功能。通过使用卤素作为立体辅助控制反应区域化学的氰氧基团环加成反应,可以获得4位和5位取代的异恶唑的区域异构体。化合物11和19b的晶体数据已给出。