Enantioselective Amine-Catalyzed [4+2] Annulations of Allenoates and Oxo-dienes: An Asymmetric Synthesis of Dihydropyrans
作者:Xiaojun Wang、Tong Fang、Xiaofeng Tong
DOI:10.1002/anie.201100945
日期:2011.5.27
dihydropyrans have been prepared in high to excellent yields and enantioselectivities (see scheme). The interaction between functional groups in the zwitterionic intermediate, which is generated by addition of the amine catalyst to the allenoate substrate, is thought to play a crucial role in the stereochemical outcome. Bn=benzyl, DMAP=4‐dimethylaminopyridine.
已经以高至优异的产率和对映选择性制备了生物学上显着的多取代的二氢吡喃(参见方案)。两性离子中间体中官能团之间的相互作用(这是通过将胺催化剂添加到烯丙酸酯底物上而产生的)被认为在立体化学结果中起着至关重要的作用。Bn =苄基,DMAP = 4-二甲基氨基吡啶。