Siebert Matthew R, Yudin Andrei K, Tantillo Dean J
Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, California 95616, USA.
Org Lett. 2008 Jan 3;10(1):57-60. doi: 10.1021/ol702623d. Epub 2007 Dec 4.
The cycloaddition of (Z)-7-(prop-1-enyl)-7-azabicyclo[4.1.0]heptane with dimethyl acetylene dicarboxylate (DMAD) was reported previously to proceed with complete stereoselectivity. Quantum chemical calculations (B3LYP) were used to evaluate the mechanism of the cyclization process, and it was discovered that a stepwise pathway is preferred. The subsequent electrocyclic ring opening reaction of the cyclobutene was also studied, and it was found that ring opening to the "methyl-in" dienamine is preferred to the "methyl-out" product by some 4-5 kcal/mol.
先前报道，(Z)-7-(丙-1-烯基)-7-氮杂双环[4.1.0]庚烷与二甲基乙炔二羧酸酯(DMAD)的环加成反应具有完全的立体选择性。用量子化学计算方法(B3LYP)评估了环化过程的机理，发现分步反应途径更有利。还研究了环丁烯随后的电环化开环反应，发现开环生成“甲基在内”的二烯胺比生成“甲基在外”的产物约有利4-5千卡/摩尔。
