- A catalytic Michael/Horner-Wadsworth-Emmons cascade reaction for enantioselective synthesis of thiochromenes
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A catalytic enantioselective sulfa-Michael/Horner-Wadsworth-Emmons reaction cascade has been developed, taking advantage of phosphonate as an electrophilic activator and a traceless binding site. Using a chiral bifunctional urea derivative as the catalyst, a variety of aryl and heteroaryl substituted thiochromenes was obtained in excellent yield with a high level of enantioselectivity. Copyright
- Choudhury, Abhijnan Ray,Mukherjee, Santanu
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supporting information
p. 1989 - 1995
(2013/08/23)
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- A versatile synthetic route to 1,5-dithiocins from o-mercapto aromatic aldehydes
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An earlier procedure for the facile preparation of benzo-fused 1,5-dithiocins 2a-2c from o-mercaptobenzaldehydes has been improved and shown to be capable of extension to the preparation of several naphthalene-derived analogues. The general method also afforded several N-alkylated 1,5-dithiocins 4, 5 by replacing NH3 with the appropriate primary amine. It was found that N-acylation of the 1,5-dithiocins was successful only with methyl chloroformate. Attempted N-phenylation met with limited success but was shown to be unnecessary since even the less reactive aniline readily undergoes the general reaction of primary amines. When simple α-amino acids, or their methyl esters, were employed as the primary amine in the reaction with o-mercaptobenzaldehyde, the formation of the N-alkylated 1,5-dithiocins 4a, 17a, 17b with accompanying loss of -COOH or -COOMe was observed, in preparatively useful yields. A mechanism is proposed for this interesting transformation.
- Still, Ian W.J.,Natividad-Preyra, Rosanne,Toste, F. Dean
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p. 113 - 121
(2007/10/03)
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- Preparation of 6,12-imino-6H,12H-dibenzo[b,f]-1,5-dithiocins
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Reaction of thiosalicylaldehydes 4a-c with ammonium acetate affords 6,12-imino-6H,12H-dibenzo[b,f]-1,5-dithiocins 2a-c in good to excellent yields. The V-shape of these molecules was confirmed by an X-ray structure determination.
- Dean Toste
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p. 6619 - 6622
(2007/10/02)
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