Entropy-Controlled Diastereoselectivity in the Photocyclization of Rigid Derivatives of <i>o</i>-Allylaniline
作者:Otman Benali、Miguel A. Miranda、Rosa Tormos、Salvador Gil
DOI:10.1021/jo020355w
日期:2002.11.1
o-allylaniline, namely 8-allyl-2-phenyl-1,2,3,4-tetrahydroquinoline (1b) and 7-(trans-2-cinnamyl)-2-methylindoline (1c), have been chosen as suitable systems to study the potential stereoselectivity of the photocyclization process. Photolysis of 1b leads to a mixture of diastereomeric lilolidines 4 (trans/cis), while 1cproduces a mixture of 4 (trans/cis) and the tetrahydropyrrolo[3,2,1-hi]indole derivatives 5 (trans/cis)
选择了o-烯丙胺的两个刚性衍生物,即8-烯丙基-2-苯基-1,2,3,4-四氢喹啉(1b)和7-(反式-2-肉桂基)-2-甲基吲哚(1c)。作为研究光环化过程潜在的立体选择性的合适系统。1b的光解反应生成非对映异构的亚油苷4(反式/顺式)的混合物,而1c产生4(反式/顺式)和四氢吡咯并[3,2,1-hi吲哚衍生物5(反式/顺式)的混合物。为了揭示非对映选择性是否可能取决于熵,已在几个温度下对1b和1c进行了光解。在两种情况下,当将ln(k(t)/ k(c))(由非对映异构体过量计算出的相对反应速率常数)相对于温度作图时,都可以观察到线性关系。然而,