Condensation of Laterally Lithiated <i>o</i>-Methyl and <i>o</i>-Ethyl Benzamides with Imines Mediated by (−)-Sparteine. Enantioselective Synthesis of Tetrahydroisoquinolin-1-ones
作者:Volker Derdau、Victor Snieckus
DOI:10.1021/jo001369+
日期:2001.3.1
The first asymmetric synthesis of tetrahydroisoquinolin-1-ones using a (-)-sparteine-mediated lateral metalation-imine addition sequence to furnish 3-phenyl tetrahydroisoquinolinones 3a with enantioselectivities up to 81% ee is described (Scheme 4). For amide 7b, imine addition products 10 and 11 have been obtained with high diastereoselectivities (91-97% de) and enantioselectivities (91-98% ee) (Scheme 8).
Ishibashi, Hiroyuki; Ohata, Kohei; Niihara, Michiyo, Journal of the Chemical Society. Perkin transactions I, 2000, vol. 4, p. 547 - 554
Arylacetic acids, when the carboxyl group is at a secondary or tertiary carbon, are decarboxylated in considerable yields on irradiation of their aqueous alkaline solutions with 254 nm light, while the corresponding free acids are not decarboxylated. Together with the simple decarboxylation reaction (type A), two other side reactions, oxidative decarboxylation (type B) and decarboxylative dimerization (type C), were observed for some compounds, particularly when >290 nm light was used. The observation of high-yield decarboxylation of angularly substituted phenanthridone derivatives suggests that the above photodecarboxylation reaction would be a useful synthetic tool, if the substrate is appropriately designed.