Reactions of 1,1-bis(N,N-dimethylamino)-1,3-butadiene with olefins. Zwitterion formation and (4+2) cycloaddition as competing pathways.
作者:Reiner Sustmann、Monika Rogge
DOI:10.1016/0040-4039(90)80202-w
日期:1990.1
Reactions of 1,1 bis(N,N-dimethylamino)-1,3-butadiene (2) with acrylonitrile and tetracyanoethylene are described. At 80°C acrylonitrile affords a (4+2) cycloadduct (3), whereas a zwitterion (4), formed from 2 and tetracyanoethylene even at −40°C, is characterized in solution and trapped as picrate. It eliminates hydrogen cyanide at T>−20°C to give a cyanine (5). Ring closure of the zwitterion either
描述了1,1双(N,N-二甲基氨基)-1,3-丁二烯(2)与丙烯腈和四氰基乙烯的反应。在80°C时,丙烯腈提供(4 + 2)环加合物(3),而即使在-40°C时,由2和四氰基乙烯形成的两性离子(4)仍在溶液中表征,并被捕获为苦味酸盐。它在T> -20°C时除去氰化氢,得到花菁(5)。未观察到两性离子与(2 + 2)或(4 + 2)环加成环的闭环。