Synthesis and highly selective Diels–Alder cycloadditions of the new dienes N-substituted 2,3,5,6-tetrahydrobenzoxazol-2-ones
作者:Rafael Martı́nez、Hugo A Jiménez-Vázquez、Francisco Delgado、Joaquı́n Tamariz
DOI:10.1016/s0040-4020(02)01536-3
日期:2003.1
and the corresponding isocyanates 2a–2c. The presence of electron-donor substituents in the aryl ring of the isocyanate gave rise to the exclusive formation of the captodative olefins 10. Diene 8a proved to be reactive and stereoselective in Diels–Alderadditions with a cyclic olefin. The reaction with acetylenic dienophiles yielded the 2,3-dihydrobenzoxazol-2-ones 21 and 24, as the products of sequential