Generation of Axially Chiral Fluoroallenes through a Copper-Catalyzed Enantioselective ß-Fluoride Elimination.
J Am Chem Soc
; 143(34): 13759-13768, 2021 09 01.
Article
em En
| MEDLINE
| ID: mdl-34465099
ABSTRACT
Herein we report the copper-catalyzed silylation of propargylic difluorides to generate axially chiral, tetrasubstituted monofluoroallenes in both good yields (27 examples >80%) and enantioselectivities (82-98% ee). Compared to previously reported synthetic routes to axially chiral allenes (ACAs) from prochiral substrates, a mechanistically distinct reaction has been developed the enantiodiscrimination between enantiotopic fluorides to set an axial stereocenter. DFT calculations and vibrational circular dichroism (VCD) suggest that ß-fluoride elimination from an alkenyl copper intermediate likely proceeds through a syn-ß-fluoride elimination pathway rather than an anti-elimination pathway. The effects of the C1-symmetric Josiphos-derived ligand on reactivity and enantioselectivity were investigated. Not only does this report showcase that alkenyl copper species (like their alkyl counterparts) can undergo ß-fluoride elimination, but this elimination can be achieved in an enantioselective fashion.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cobre
/
Fluoretos
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos