Design of Brønsted Acid-Assisted Chiral Lewis Acid (BLA) Catalysts for Highly Enantioselective Diels−Alder Reactions
作者:Kazuaki Ishihara、Hideki Kurihara、Masayuki Matsumoto、Hisashi Yamamoto
DOI:10.1021/ja9810282
日期:1998.7.1
Bronsted acid-assisted chiral Lewis acid (BLA) was highly effective as a chiral catalyst for the enantioselective Diels−Alder reaction of both α-substituted and α-unsubstituted α,β-enals with various dienes. Hydroxy groups in optically active binaphthol derivatives and boron reagents with electron-withdrawing substituents were used as Bronsted acids and Lewis acids, respectively. Intramolecular Bronsted
布朗斯台德酸辅助的手性路易斯酸 (BLA) 作为手性催化剂非常有效,可用于 α-取代和 α-未取代的 α,β-烯醛与各种二烯的对映选择性 Diels-Alder 反应。光学活性联萘酚衍生物中的羟基和具有吸电子取代基的硼试剂分别用作布朗斯台德酸和路易斯酸。手性 BLA 催化剂中的分子内布朗斯台德酸在加速 Diels-Alder 反应速率和产生高水平的对映选择性方面发挥了重要作用。特别是,由于手性 BLA 催化剂中羟基芳基在过渡态组装中的分子内氢键相互作用和有吸引力的 π-π 供体-受体相互作用,实现了优异的对映选择性。