Reaction of lithium dialkylcuprates with S-2-pyridyl thioates in the presence of oxygen. A carboxylic ester synthesis
作者:Sunggak Kim、Jae In Lee、Bong Young Chung
DOI:10.1039/c39810001231
日期:——
Reaction of lithiumdialkylcuprates with S-2-pyridyl thioates in the presence of oxygen affords carboxylic esters in high yields, whereas under nitrogen it affords ketones.
Water-Soluble Acylating Agents: Preparation of 2-Acylthio-1-alkylpyridinium Salts and Acylation of Phenols, Acids, and/or Amines with These Salts in an Aqueous Phase
Reaction of phenols, amines, and acids with 2-benzoylthio-1-methylpyridiniumchloride prepared in situ from benzoyl chloride and 1-methyl-2(1H)-pyridinethione, afforded the corresponding benzoyl derivatives in good yields. In the reaction of p-nitrophenol, even a catalytic amount of 1-methyl-2(1H)-pyridinethione proved to be effective. Similar reactions of p-nitrophenol with isobutyryl chloride and acetyl
tested as chiral auxiliaries in the stereoselectivesynthesis of β-lactams by condensation of the titanium enolates of 2-pyridyl thioesters with chiral imines. The amines were selected among the following classes of compounds: benzylic amines, β-aminoalcohols, β-heterosubstituted α-aminoesters. Inexpensive and available in both enantiomeric forms α-methylbenzylamine was identified as the chiral auxiliary
Highly stereocontrolled synthesis of substituted propiolactones and butyrolactones from achiral lithium enolates and homociral aldehydes
作者:Iosune Arrastia、Begon̄a Lecea、Fernando P. Cossío
DOI:10.1016/0040-4039(95)02139-6
日期:1996.1
Lithiumenolates derived from achiral thiol esters react in a highly stereoselective fashion with homochiral aldehydes to yield the corresponding 2-oxetanones. The stereochemical outcome of the reaction corresponds to a non-chelation control. except when O-silylated mandelaldehyde is used. The propiolactones thus formed are efficiently transformed into δ-lactones via Lewis acid promoted dyotropic rearrangements
The enolates derived from 2-pyridylthioesters by reaction with BCl3 ·SMe2 and enantiomerically pure aminoalcohols react with aromatic imines in an enantioselective fashion (ee up to 78%) to afford β-lactams in a convenient one-pot procedure.