Allenylic Carbonates in Enantioselective Iridium-Catalyzed Alkylations.
J Am Chem Soc
; 140(13): 4697-4704, 2018 04 04.
Article
en En
| MEDLINE
| ID: mdl-29488753
ABSTRACT
An enantioconvergent C(sp3)-C(sp3) coupling between racemic allenylic electrophiles and alkylzinc reagents has been developed. An Ir/(phosphoramidite,olefin) catalyst provides access to highly enantioenriched allenylic substitution products (93-99% ee) with complete regiocontrol (>501 rr in all cases) over the corresponding 1,3-diene isomers which are obtained predominantly when other metal catalysts are emplyed. The synthetic utility of the products obtained was highlighted in a variety of stereoselective transition metal-catalyzed difunctionalization reactions. Furthermore, a combination of experimental and theoretical studies provide support for a putative reaction mechanism wherein enantiodetermining C-C coupling occurs via nucleophilic attack on a highly planarized aryl butadienylium π-system that is coordinated to the Ir center in an η2-fashion.
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1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Am Chem Soc
Año:
2018
Tipo del documento:
Article
País de afiliación:
Suiza