Diastereoselective Synthesis of Substituted Tetrahydroquinoline-4-carboxylic Esters by a Tandem Reduction−Reductive Amination Reaction
作者:Richard A. Bunce、Derrick M. Herron、Lara B. Johnson、Sharadsrikar V. Kotturi
DOI:10.1021/jo001761n
日期:2001.4.1
A diastereoselective synthesis of 1-methyl-2-alkyl- and 2-alkyl-1,2,3,4-tetrahydroquinoline-4-carboxylic esters has been developed from methyl (2-nitrophenyl)acetate (1). The method involves alkylation of 1 with an allylic halide, ozonolysis of the double bond, and catalytic hydrogenation. The final hydrogenation initiates a tandem sequence involving (1) reduction of the aromatic nitro group, (2) condensation
由(2-硝基苯基)乙酸甲酯(1)开发了1-甲基-2-烷基-和2-烷基-1,2,3,4-四氢喹啉-4-羧酸酯的非对映选择性合成。该方法包括用烯丙基卤化物烷基化1,双键的臭氧分解,以及催化氢化。最终的氢化反应引发了一个串联反应,包括(1)芳族硝基的还原,(2)苯胺或羟胺的缩合(8)氮与侧链羰基的缩合,(3)所得氮中间体的还原,和(4) )将四氢喹啉用在臭氧分解中产生的甲醛进行还原胺化,得到(+/-)-1-甲基-2-烷基-1,2,3,4-四氢喹啉-4-羧酸甲酯。在氢化之前除去甲醛,得到简单的(+/-)-2-烷基衍生物。以高收率分离产物,其为具有相对于C-4羧酸酯顺式的C-2烷基的单一非对映异构体。该反应已扩展到具有相似的高非对映选择性的三环结构的合成。