Enantioselective Synthesis of (2-Pyridyl)alanines via Catalytic Hydrogenation and Application to the Synthesis of <scp>l</scp>-Azatyrosine
作者:Maciej Adamczyk、Srinivasa Rao Akireddy、Rajarathnam E. Reddy
DOI:10.1021/ol016455q
日期:2001.10.1
for the synthesis of (2-pyridyl)alanines 2a-b was developed by converting (2-pyridyl)dehydroamino acid derivatives 1a-b to the corresponding N-oxides 3a-b followed by asymmetric hydrogenation using (R,R)-[Rh(Et-DUPHOS)(COD)]BF(4) [(R,R)-6] catalyst and subsequent N-oxide reduction in 80-83% ee. This methodology was applied to the total synthesis of L-azatyrosine [(+)-12], an antitumor antibiotic, starting
[反应:见正文]通过将(2-吡啶基)脱氢氨基酸衍生物1a-b转化为相应的N-氧化物3a-b,然后进行不对称氢化,开发了一种合成(2-吡啶基)丙氨酸2a-b的新方法。使用(R,R)-[Rh(Et-DUPHOS)(COD)] BF(4)[(R,R)-6]催化剂,随后在80-83%ee中还原N-氧化物。该方法学应用于从(5-苄氧基)-2-吡啶基甲醇(7)开始以大于96%的对映体纯度合成L-氮杂酪氨酸[(+)-12],一种抗肿瘤抗生素。