Single and double asymmetric induction in Diels-Alder cycloadditions with chiral acylnitroso dienophiles
作者:Albert Defoin、Joaquim Pires、Isabelle Tissot、Théophile Tschamber、Daniel Bur、Margareta Zehnder、Jacques Streith
DOI:10.1016/s0957-4166(00)80021-x
日期:1991.1
achiral 1-silyloxybutadiene 1a with the chiral acyinitroso dienophile 2a gave cycloadduct 4 in high diastereomeric excess (d.e. > 98 %), a result which is undoubtedly due to the C-2 symmetrical chiral dimethylpyrrolidine inductor. Excellent d.e. was also observed when the (R)-prolinol dienophile 2d was reacted with the chiral diene 1b (d.e. = 96 %), whereas cycloaddition of the (S) enantiomer 2e with 1b gave
非手性1-甲硅烷氧基丁二烯1a与手性酰基亚硝基二亲二烯体2a的Diels-Alder反应产生高非对映异构体过量的环加合物4(de> 98%),这无疑是由于C-2对称的手性二甲基吡咯烷诱导剂。当(R)-脯氨醇双亲二烯体2d与手性二烯1b反应时(de = 96%),也观察到了极好的de(de),而(S)对映异构体2e与1b的环加成反应仅引起较差的不对称诱导(de= 4%)。后两个示例很好地说明了“不匹配对”(1b / 2d)与“不匹配对”(1b / 2e)对双重不对称感应的影响。本文所有报道的Diels-Alder环加成均是区域特异性的。