作者:Thomas S. Hughes、Barry K. Carpenter
DOI:10.1039/a904369a
日期:——
The Myers–Saito cycloaromatization of enyne allenes is proposed to consist of two parallel mechanisms, one involving a biradical and the other with dipolar character. MCSCF calculations suggest that a nonplanar cyclic allene could be fairly close in enthalpy to the biradical, while the planar zwitterion originally proposed as a possible second intermediate is in fact a transition state for the interconversion
迈恩斯-塞托烯烯的环芳烃化被认为是由两个平行的机制组成,一个涉及双自由基,另一个具有偶极特性。MCSCF计算表明,非平面环状烯与双自由基的焓可能相当接近,而最初提议作为可能的第二中间体的平面两性离子实际上是两个对映体环状烯的互变的过渡态。竞争性诱捕实验排除了单一中间体的存在,并且与平行途径的参与一致。(Z)-庚-1,2,4-三烯-6-炔在环戊二烯中的反应产生了不可分离的两种四环产物的混合物,其结构通过2-D NMR得以阐明。