Diastereoselective Conjugate Addition to (+)-Camphorsulfonic Acid Derived Nitroalkenes: Synthesis of α-Hydroxy and α-Amino Acids
作者:Anthony G. M. Barrett、D. Christopher Braddock、Paul W. N. Christian、Daniel Pilipauskas、Andrew J. P. White、David J. Williams
DOI:10.1021/jo980582r
日期:1998.8.1
Diastereoselective tandem conjugate addition of both oxygen- and nitrogen-centered nucleophiles to the novel (1S)-10-camphorsulfonic acid derived nitroalkenes 9, 10, and 11 and ozonolysis gave the alpha-hydroxy and alpha-amino thiol acid derivatives 12, 13, and 14. In all cases, the (R)-diastereomer was formed as the major component albeit with only modest levels of selectivity (33-71% de). The structures
将以氧和氮为中心的亲核试剂非对映选择性串联共轭添加到新型(1S)-10-樟脑磺酸衍生的硝基烯烃9、10和11中,并进行臭氧分解,得到α-羟基和α-氨基硫醇酸衍生物12、13 14.在所有情况下,(R)-非对映异构体都是主要成分,尽管选择性水平适中(33-71%de)。产物的结构和迈克尔加成反应的立体化学是通过硝基烯烃9和10以及(2S)-12c和(2R)-13a的X射线晶体学研究以及通过(S)-丙氨酸的替代合成而明确确定的(S)-缬氨酸和(S)-乳酸乙酯。