[4 + 2] Dimerization and Cycloaddition Reactions of α,β-Unsaturated Selenoaldehydes and Selenoketones
作者:Guang Ming Li、Shuqiang Niu、Masahito Segi、Ralph A. Zingaro、Hiroaki Yamamoto、Kentaro Watanabe、Tadashi Nakajima、Michael B. Hall
DOI:10.1021/jo982028n
日期:1999.3.1
undergo regioselective [4 + 2] dimerization via a "head-to-head" oriented transition state to afford diselenin derivatives (trans and cis isomers). Theoretical calculations at the density functional theory level show that this selectivity occurs because the "head-to-head" dimerization is thermodynamically favored over the "head-to-tail" by about 14 kcal/mol. Both dimerization reactions have low energy barriers: