Facial selectivity in the inverse-electron-demand Diels-Alder reaction: additions to 1,2,3,4,5-pentachloro-5-methoxy-1,3-cyclopentadiene
摘要:
Dienophiles of various types underwent Diels-Alder cycloaddition to 1,2,3,4,5-pentachloro-5-methoxy-1,3-cyclopentadiene (1). Some reactions were predicted to proceed in the inverse-electron-demand mode whereas others were of the ''normal'' electronic configuration. The facial selectivity in, every reaction was the same. Addition was exclusively to the face of 1 syn to its methoxy group. The facial selectivity was consistent with steric and/or torsional control of facial selectivity rather than a consequence of a stereoelectronic phenomenon.