Application of Zinc(II)–Binol for the Formal Aza-Diels–Alder Reaction ofN-Arylimines with Danishefsky's Diene: CD-Based Absolute Stereochemistry Determination, Origin of Asymmetric Induction and Mechanistic Considerations
作者:Lorenzo Di Bari、Stéphane Guillarme、John Hanan、Andrew P. Henderson、Judith A. K. Howard、Gennaro Pescitelli、Michael R. Probert、Piero Salvadori、Andrew Whiting
DOI:10.1002/ejoc.200700731
日期:2007.12
Zinc(II)–binol has been employed as an efficient Lewis acid catalyst (10 or 100 mol-% loading) for the formal aza-Diels–Alder reaction of ester, furyl and dimethyl acetal-substituted N-aryl imines. Asymmetric induction varies from poor to good, with the major enantiomer obtained being (S) when the (S)-binol complex has been employed. The absolute stereochemistry of the dimethyl acetal-substituted cycloaduct
锌 (II)-二元醇已被用作有效的路易斯酸催化剂(10 或 100 mol% 负载量),用于酯、呋喃基和二甲基缩醛取代的 N-芳基亚胺的正式氮杂-狄尔斯-阿尔德反应。不对称诱导从差到好变化,当使用 (S)-binol 复合物时,获得的主要对映异构体是 (S)。二甲基缩醛取代的环加合物的绝对立体化学由 CD 确定,并且有效的氮杂-Diels-Alder 反应和不对称诱导都被认为依赖于双齿锌-亚胺配合物的形成。这些复合体已使用半经验方法建模。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)