New chiral alanine template with a 1,2,3,6-tetrahydro-2-pyrazinone structure for the asymmetric synthesis of α-methyl α-amino acids
作者:Tomás Abellán、Carmen Nájera、José M Sansano
DOI:10.1016/s0957-4166(98)00208-0
日期:1998.7
(R)-6-Isopropyl-5-phenyl-1,2,3,6-tetrahydro-2-pyrazinone, prepared from (R)-valine and (S)-alanine, reacts with activated alkyl halides and electrophilic olefins under solid–liquid PTC conditions with K2CO3 as base, at room temperature and with high diastereoselectivity (>94%). The palladium-catalyzed allylation reaction of this alanine derivative under neutral conditions at room temperature also takes
由(R)-缬氨酸和(S)-丙氨酸制得的(R)-6-异丙基-5-苯基-1,2,3,6-四氢-2-吡嗪酮在固体下与活化的烷基卤化物和亲电烯烃反应–在室温和高非对映选择性(> 94%)的条件下,以K 2 CO 3为碱的液体PTC条件。在室温下,在中性条件下,该丙氨酸衍生物的钯催化的烯丙基化反应也发生,其de> 96%。烷基化的吡嗪酮的最终水解得到对映体纯的α-甲基α-氨基酸。