Stereoselective Synthesis of Unsaturated and Functionalized <scp>l</scp>-NHBoc Amino Acids, Using Wittig Reaction under Mild Phase-Transfer Conditions
作者:Emmanuelle Rémond、Jérôme Bayardon、Marie-Joëlle Ondel-Eymin、Sylvain Jugé
DOI:10.1021/jo3013622
日期:2012.9.7
afford the corresponding unsaturated amino acids without racemization. Thus, the reaction with substituted aldehydes allows to graft various functionalized groups on the lateral chain of the amino acid, such as trifluoromethyl, cyano, nitro, ferrocenyl, boronato, or azido. In addition, the reaction of the amino acid Wittig reagent with α,β-unsaturated aldehydes leads to amino acids bearing a diene on
通过将熔融的三苯基膦与衍生自1-天冬氨酸的γ-碘NHBoc-氨基酯进行季铵化,描述了一种新的氨基酸phospho盐的立体选择性合成。羧酸官能团的脱保护得到带有游离羧酸基团的phospho盐是通过钯催化的脱盐基反应实现的。在固-液相转移条件下,在氯苯中,在K 3 PO 4存在下,该phospho盐用于与芳族或脂肪族醛和三氟苯乙酮的Wittig反应中作为弱碱,无需消旋即可得到相应的不饱和氨基酸。因此,与取代的醛的反应允许在氨基酸的侧链上接枝各种官能化的基团,例如三氟甲基,氰基,硝基,二茂铁基,硼酸钠基或叠氮基。另外,氨基酸Wittig试剂与α,β-不饱和醛的反应导致在侧链上带有二烯的氨基酸。最后,这种氨基酸phospho盐似乎是制备不饱和和非蛋白原性α-氨基酸的一种新的有力工具,可直接用于合成定制肽。