Highly Stereoselective Strecker Synthesis Induced by a Slight Modification of Benzhydrylamine from Achiral to Chiral
| Autor: | Shohei Aiba, Yuji Tokunaga, Tsuneomi Kawasaki, Takuya Yamada, Naoya Takamatsu |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Chemistry Stereochemistry Organic Chemistry Strecker amino acid synthesis Diastereomer Enantioselective synthesis Substrate (chemistry) General Chemistry 010402 general chemistry 01 natural sciences Catalysis 0104 chemical sciences Amino acid Amine gas treating Stereoselectivity Chirality (chemistry) |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 24(6) |
| ISSN: | 1521-3765 |
| Popis: | 2-Methylbenzhydrylamine is a chiral variant of achiral benzhydrylamine; however, the chirality formed from the small difference between the phenyl and o-tolyl groups is not expected to induce sufficient stereoselectivity in conventional homogeneous reactions. Initiated by the spontaneous formation and asymmetric amplification of the enantioenriched N-benzhydryl-α-aminonitrile forming conglomerate, we here report that (S)- and (R)-configured title amine, upon the Strecker reaction with achiral aldehydes and HCN, afford the corresponding α-aminonitriles with up to >99.5 % diastereomeric excess, in conjunction with an enhancement of chirality in the solid state. l-Alanine with 98 % ee was synthesized from the (S)-amine by using the method discussed here. Achiral aromatic and heteroaromatic aldehydes could also be successfully utilized to afford chiral α-aminonitriles in a highly stereoselective manner. The stereodivergent synthesis of styrylglycine nitriles has also been accomplished by using racemic and enantioenriched 2-methylbenzhydrylamine. Thus, accompanied with a small rearrangement of the common substrate from achiral toward chiral, the present reactions induce an enhancement of chirality, and expands the concept of stereoselective synthesis to increase the opportunity to access highly enantioenriched compounds such as α-amino acids. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text