A Brønsted Acid-Amino Acid as a Synergistic Catalyst for Asymmetric List-Lerner-Barbas Aldol Reactions

Ramachary, Dhevalapally B. ; Shruthi, Kodambahalli S. (2016) A Brønsted Acid-Amino Acid as a Synergistic Catalyst for Asymmetric List-Lerner-Barbas Aldol Reactions Journal of Organic Chemistry, 81 (6). pp. 2405-2419. ISSN 0022-3263

Full text not available from this repository.

Official URL: http://doi.org/10.1021/acs.joc.5b02896

Related URL: http://dx.doi.org/10.1021/acs.joc.5b02896

Abstract

Herein, for the first time, a combination of l-amino acid, (R)-5,5-dimethyl thiazolidinium-4-carboxylate (l-DMTC) with simple Brønsted acid TFA is reported as the suitable synergistic catalyst for the List-Lerner-Barbas aldol (LLB-A) reaction of less reactive 2-azidobenzaldehydes with various ketones at ambient temperature to furnish the optically active functionalized (2-azidophenyl)alcohols with very good yields, dr’s, and ee’s. This method gives first time access to the novel azido-containing multifunctional compounds, which are applicable in material to medicinal chemistry. Chiral functionalized (2-azidophenyl)alcohols were transformed into different molecular scaffolds in good yields with high selectivity through Lewis acid mediated NaBH4 reduction, aza-Wittig and Staudinger reaction (azide reduction), followed by oxidative cyclizations, allenone synthesis, and click reaction, respectively. Chiral LLB-A products might become suitable starting materials for the total synthesis of natural products, ingredients, and inhibitors in medicinal chemistry. The mechanistic synergy of l-DMTC with TFA to increase the rate and selectivity of LLB-A reaction in DMSO-D6 is explained with the controlled and online NMR experiments.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:120654
Deposited On:03 Jul 2021 06:32
Last Modified:03 Jul 2021 06:32

Repository Staff Only: item control page