A novel method for the asymmetric synthesis of 4,4-disubstituted 2-cyclopentenones from optically active 1-chlorovinyl p-tolyl sulfoxides and its application to the asymmetric total synthesis of (+)-α-cuparenone
作者:Tsuyoshi Satoh、Masaaki Yoshida、Yasuhiro Takahashi、Hiroyuki Ota
DOI:10.1016/s0957-4166(02)00797-8
日期:2003.1
of the 1-chlorovinyl p-tolyl sulfoxides with cyanomethyllithium at −78°C to room temperature gave optically active 2-amino-1-cyano-5,5-disubstituted-1,3-cyclopentadienes in high yields with very high asymmetric induction from the stereogenic center of the sulfoxide moiety. A mechanism for the asymmetric induction is proposed. The products were treated with phosphoric acid in acetic acid at reflux temperature
对映体纯1-氯乙烯基p具有在2-位上有两个不同的取代基间-甲苯基砜从不对称酮合成和(- [R )- ( - ) -氯甲基p -甲苯基砜中的三个步骤。1-氯乙烯基p的处理-甲苯基亚砜与氰基甲基锂在-78°C至室温下以高收率得到光学活性的2-氨基-1-氰基-5,5-二取代-1,3-环戊二烯,并从亚砜的立体异构中心非常不对称地诱导部分。提出了一种非对称感应的机制。将产物在回流温度下用磷酸的乙酸溶液处理,以良好的产率得到对映体纯的4,4-二取代的2-环戊烯酮。作为该合成方法的一种应用,描述了由甲基4-甲基苯基酮进行的相对短的(七个步骤)全不对称合成(+)-α-cuparenone。