Asymmetric catalytic alkynylation of thiazolones and azlactones for synthesis of quaternary α-amino acid precursors
Asymmetric alkynylation of thiazolones and azlactones with alkynylbenziodoxolones as the electrophilic alkyne source catalyzed by thiourea phosphonium salt is described. By using thiazolones as nucleophiles, the desired alkyne functionalized thiazolones were obtained in 55-89% yields with 31-86% ee....
Saved in:
Published in | Organic & biomolecular chemistry Vol. 19; no. 23; pp. 587 - 592 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
CAMBRIDGE
Royal Soc Chemistry
16.06.2021
Royal Society of Chemistry |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Asymmetric alkynylation of thiazolones and azlactones with alkynylbenziodoxolones as the electrophilic alkyne source catalyzed by thiourea phosphonium salt is described. By using thiazolones as nucleophiles, the desired alkyne functionalized thiazolones were obtained in 55-89% yields with 31-86% ee. Azlactones gave the desired products in comparable yields with lower enantioselectivities. Ring-opening of the alkynylation products led to α,α-disubstituted α-amino acid derivatives efficiently without loss of enantioselectivity.
Under 5 mol% of phosphonium salt catalyst derived from chiral amino alcohol, asymmetric alkynylation of thiazolones and azlactones has been developed. |
---|---|
Bibliography: | Electronic supplementary information (ESI) available. CCDC 2072337 For ESI and crystallographic data in CIF or other electronic format see DOI 10.1039/d1ob00582k ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1477-0520 1477-0539 |
DOI: | 10.1039/d1ob00582k |