作者:J. Kalo、D. Ginsburg、E. Vogel
DOI:10.1016/0040-4020(77)80410-9
日期:——
We show again that compounds containing CO groups which are capable of secondary orbital interactions with the dienophile, 4-phenyl-1,2,4-triazoline-3,5-dione cause reaction to occur from above. However, in substrates which do not have capability for overlap with the dienophile nitrogen lone pairs and, on the contrary, exert steric hindrance to topside reaction, reaction with the first equivalent of
我们再次表明,含有CO基团的化合物能够与亲双烯体4-苯基-1,2,4-三唑啉-3,5-二酮发生二次轨道相互作用,从而导致反应从上方发生。然而,在不具有与亲双烯体氮孤对重叠的能力并且相反地对上侧反应施加空间位阻的底物中,与第一当量亲双烯体的反应从下方发生。当第二当量可以反应时,它又从上方反应,这也是相对的空间原因。