Practical enantioselective arylation and heteroarylation of aldehydes with in situ prepared organotitanium reagents catalyzed by 3-aryl-H8-BINOL-derived titanium complexes.
Chemistry
; 19(15): 4896-905, 2013 Apr 08.
Article
en En
| MEDLINE
| ID: mdl-23436626
ABSTRACT
A highly efficient and practical method for the catalytic enantioselective arylation and heteroarylation of aldehydes with organotitanium reagents, prepared in situ by the reaction of aryl- and heteroaryllithium reagents with ClTi(OiPr)3, is described. Titanium complexes derived from DPP-H8 -BINOL (3d; DPP=3,5-diphenylphenyl) and DTBP-H8 -BINOL (3e; DTBP=3,5-di-tert-butylphenyl) exhibit excellent catalytic activity in terms of enantioselectivity and turnover efficiency for the transformation, providing diaryl-, aryl heteroaryl-, and diheteroarylmethanol derivatives in high enantioselectivity at low catalyst loading (0.2-2 mol%). The reaction begins with a variety of aryl and heteroaryl bromides through their conversion into organolithium intermediates by Br/Li exchange with nBuLi, thus providing straightforward access to a range of enantioenriched alcohols from commercially available starting materials. Various 2-thienylmethanols can be synthesized enantioselectively by using commercially available 2-thienyllithium in THF. The reaction can be carried out on a 10 mmol scale at 0.5 mol% catalyst loading, demonstrating its preparative utility.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Compuestos Organometálicos
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Titanio
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Alcoholes
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Aldehídos
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Naftoles
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Japón