Chiral dioxomolybdenum(VI) complexes for enantioselective alkene epoxidation

• Type: Article in International Scientific Journal
• Date: 2001

Authors

Goncalves, IS (Author) Other; Santos, AM (Author) Other; Romao, CC (Author) Other; Lopes, AD (Author) Other; Rodriguez Borges, JE (Author) FCUP; Pillinger, M (Author) Other; Ferreira, P (Author) Other; Rocha, J (Author) Other; Kuhn, FE (Author) Other

Journal

Title: Journal of Organometallic Chemistry

Vol. 626

Pages: 1-10

ISSN: 0022-328X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 68 Citations

Scopus - 71 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-VST

DOI: 10.1016/s0022-328x(00)00790-7

Abstract (EN): Chiral dioxomolybdenum(M) complexes of the type MoO2Cl2(L*) (L* = oxime), MoO2(THF)(2)L* (L* = cis-p-menthane-3,8-diol) and MoO2Cl(THF)L* (L* = 8-phenylthioneomenthol and 8-phenylthioisoneomenthol) have been prepared in good yields by reacting MoO2Cl2(THF)(2) with the appropriate chiral organic bidentate O,O-, O,N- and O,S-ligands. The complexes were characterised by solution NMR (H-1, C-13, Mo-95) and IR spectroscopy as well as elementary analysis, and were evaluated as catalysts in solution for the asymmetric epoxidation of cis-beta -methylstyrene by tert-butylhydroperoxide (TBHP). The cis-diol complex shows high catalytic activity and enantiomeric excesses of up to 25%. An attempt was made to immobilise the complex MoO2(THF)Cl[(-)-8-phenylthioneomenthol] within the channels of MCM-41 mesoporous silica by using a tethering ligand [L = NC(CH2)(3)Si(OEt)(3)]. The material was characterised by powder X-ray diffraction (XRD), IR spectroscopy and magic-angle-spinning (MAS) NMR (C-13, Si-29). Catalytic examinations demonstrated that it was active in the epoxidation of cyclooctene by TBHP.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10