Facile Non-Racemizing Route for the N-Alkylation of Hindered Secondary Amines
作者:Shabana S. Insaf、Donald T. Witiak
DOI:10.1055/s-1999-3399
日期:1999.3
A simple, generally high yielding, method for the N-alkylation of sterically hindered secondary amines bearing α-substituents is described. Alkyl tosylates in the presence of 1,2,2,6,6-pentamethylpiperidine and toluene are essential for the production of the respective tertiary amines. Chiral amino acid derivatives studied do not racemize under the reaction conditions.
Synthesis of All Distinct α-Methyl-Substituted Isomers of Amino Bis(2,2′-Ethanoic Acid) Diethyl Ester and Ethylene Diamine Tetraacetic Acid Tetraethyl Ester Scaffolds
作者:Shabana S Insaf、Donald T Witiak
DOI:10.1016/s0040-4020(00)00103-4
日期:2000.4
The syntheses of three dialkylated and six tetraalkylated ethylene diamine tetraacetic acid tetraesters is described. The dialkylated derivatives were synthesized by a convergent non-racemizing route to yield three enantiomerically and diastereomerically pure tetraesters (SS)-, (RR)- and (R∗S∗)- in 55–57% yields from alanine ethyl ester 1. Enantiomerically and diastereomerically pure tetraalkylated