Asymmetric synthesis of isoquinuclidines by Diels–Alder reaction of 1,2-dihydropyridine utilizing a chiral Lewis acid catalyst
作者:Chigusa Seki、Masafumi Hirama、N.D.M. Romauli Hutabarat、Junko Takada、Chonticha Suttibut、Hideto Takahashi、Takuya Takaguchi、Yoshihito Kohari、Hiroto Nakano、Koji Uwai、Nobuhiro Takano、Mitsukuni Yasui、Yuko Okuyama、Mitsuhiro Takeshita、Haruo Matsuyama
DOI:10.1016/j.tet.2011.12.041
日期:2012.2
(up to 97% de) by Diels–Alder reaction of 1 with (4R)-2 using Cu(OTf)2/(4S,4′S)-bis(oxazoline) catalyst 8 as a chiral Lewis acid catalyst in dichloromethane at 0 °C. In these reactions, the choice of solvent and the combination of titanium-(2R,3R)-TADDOLate 4 or Cu(II)/(4S,4′S)-bis(oxazoline) 8} and dienophile (4S)-2 or (4R)-2} are very important. The stereochemistry of endo-(7R)-3 has been established
通过1-(苯氧羰基)的Diels-Alder反应,高收率地获得了手性异喹啉环衍生物2-氮杂双环[2.2.2]辛烷环系统,内-(7 R)-3,具有极好的非对映选择性(高达92%de) )-1,2-二氢吡啶1与N-丙烯酰基-(4 S)-4-苄基恶唑烷-2--2- (4 S)-2的反应,使用钛-(2 R,3 R)-TADDOLate 4作为手性路易斯酸催化剂在0°C的甲苯中。另一方面,内-(7 S)-3通过使用Cu(OTf)2 /(4 S,4 'S)-双(恶唑啉)催化剂与1(4 R)-2进行Diels-Alder反应,以良好的非对映选择性(高达97%de)获得了高收率的化合物。在0°C下为二氯甲烷中的8手性路易斯酸催化剂。在这些反应中,选择溶剂以及钛-(2 R,3 R)-TADDOLate 4 or Cu(II)/(4 S,4 'S)-双(恶唑啉)8 }和亲二烯体的组合(4 S)-2 或(4