Novel Synthesis of 3,4-Diaminobutanenitriles and 4-Amino-2-butenenitriles from 2-(Cyanomethyl)aziridines through Intermediate Aziridinium Salts: An Experimental and Theoretical Approach
作者:Matthias D'hooghe、Veronique Van Speybroeck、Andries Van Nieuwenhove、Michel Waroquier、Norbert De Kimpe
DOI:10.1021/jo0704210
日期:2007.6.1
1-Arylmethyl-2-(cyanomethyl)aziridines were transformed into 4-(N,N-bis(arylmethyl)amino)-3-(pyrrolidin-1-yl)butanenitriles and 4-(N,N-bis(arylmethyl)amino)-2-butenenitriles via 4-(N,N-bis(arylmethyl)amino)-3-bromobutanenitriles in high yields and purity. The key steps involve the unprecedented regiospecific ring opening of intermediate 2-(cyanomethyl)aziridinium salts by bromide and pyrrolidine in acetonitrile, exclusively at the substituted aziridine carbon atom. The results were rationalized on the basis of ab initio calculations.
An efficient and practical EPC synthesis of β-amino acids from L-asparagine
作者:Peter Gmeiner
DOI:10.1002/ardp.2503240906
日期:——
The synthesis of enantiomerically pure β‐arnino acids (1a‐c) via an O‐activated equivalent of β‐homoserine is discussed. The chiral synthon 2 was planned to be represented by (S)‐3‐N,N‐dibenzylamino‐4‐mesyloxybutanoic acid methyl ester (3) or by (S)‐3‐N,N‐dibenzylamino‐4‐mesyloxybutanenitrile (6). Both intermediates should be approached from L‐aspartic acid 4 or L‐asparagine 5 through selective reduction
讨论了通过 O 激活的 β-高丝氨酸等价物合成对映体纯 β-氨基酸 (1a-c)。手性合成子 2 计划由 (S) -3 - N, N - 二苄基氨基 - 4 - 甲氧基丁酸甲酯 (3) 或 (S) -3 - N, N - 二苄基氨基 - 4 - 甲氧基丁腈 (6 )。这两种中间体都应该通过选择性还原 α-羧基从 L-天冬氨酸 4 或 L-天冬酰胺 5 中得到。结果表明,只有腈 6 适合预想的 β-氨基酸合成,因为醇 14——3 的合成前体——对分子内亲核攻击不稳定以完成手性结构单元 15。甲磺酸酯 6 与不同的'吉尔曼反应铜酸盐'得到3-N,N-二苄基氨基腈衍生物22a-c,它可以很容易地脱保护以从天冬酰胺中以 23-36% 的总产率得到目标化合物 1a-c。相比之下,作为更高阶“Lipshutz 铜酸盐”示例的 Me2Cu (CN) Li2 没有提供所需的替代产物 22a。通过将甲酯 24