US EPA

7606146 

Journal Article 

Catalytic conjugate addition promoted by the copper(i)monothiobinaphthol system. Part 3.1 Comparison of three thiolate-based catalytic systems 

Bennctt, SMW; Brown, SM; Conole, G; Dennis, MR; Fraser, PK; Radojevic, S; Mcpartlin, M; Topping, CM; Woodward, S 

1999 

Journal of the Chemical Society, Perkin Transactions 1
ISSN: 1472-7781
EISSN: 1364-5463 

21 

3127-3132 

English 

Monothiobinaphthol (MTB, 2-hydroxy-2′-rnercapto-l,l′-binaphthyl undergoes S-alkylation with BuBr and a,co-dihalides to afford thioether species. The precursor to MTB, 2-(Ar,Ar-dimethylcarbamoyloxy)-2′-(N,Ndimethylcarbamoylthio)-!,! ′-binaphthyl, undergoes anionic Fries rearrangement of the O-aryl carbamate to afford a crystallographically characterised amido species. Hydrolysis of this species affords the 3-C(O)NMe2 analogue of MTB. These MTB-bascd ligand systems have been tested in asymmetric conjugate addition reactions of cyclic and acyclic enones and compared with l,l′-bi(2-thionaphthol). Active catalysts are formed in all cases but only low enantioselectivities are realised (0-55% ee). Full conditions for the separation of the enantiomeric conjugate addition products are reported. ©The Royal Society of Chemistry 1999.