A simple zincchloridemediated cyclization of ynamidyl N‐carbamates or 2‐ynamidyl‐(hetero)arylcarboxylates is achieved under mild reaction conditions, leading to the synthesis of useful heterocyclic scaffolds, 3H‐oxazol‐2‐ones and pyrrolo‐oxazin‐1‐ones, with good yields.
A mild and efficient methodology involving Pd(PPh3)4-catalyzed intramolecular cyclization of N-alkynyl alkyloxycarbamates with CuCl2 or CuBr2 for the synthesis of 4-halo-oxazolones was developed. This reaction exhibiting good functional tolerance provided a new, efficient, and rapid synthetic process to 4-halo-oxazolones. The resulting 4-halo-oxazolones can serve as great potential precursors for the
Using cheap and readily accessible CuCl as the catalyst, an operationally simple and efficient method for the synthesis of 3,5-disubstituted oxazolones has been realized by the cyclization of N-alkynyl tert-butyl carbamates. The reaction proceeds under mild reaction conditions and shows good functional group compatibility.
The hypervalent iodine reagent PhI(OAc)2 (PIDA) mediated the formal oxidative C=Cbond cleavage and subsequent cyclization of internal olefins, that is, α‐oxo‐ketene N,N‐acetals, which afforded substituted oxazolines. Isothiazoline derivatives were obtained from the reactions of α‐thioxo‐ketene N,N‐acetals with PIDA under the same conditions. Hydrolysis of the resultant oxazoline derivatives led to
Synthesis of 2-Oxazolones and α-Aminoketones via Palladium-Catalyzed Reaction of β,β-Dibromoenamides
作者:David I. Chai、Laura Hoffmeister、Mark Lautens
DOI:10.1021/ol102634c
日期:2011.1.7
beta,beta-Dibromoenamides show two different interesting reactivities based on the choice of R group under the reaction conditions. On the basis of mechanistic studies, both reactions proceed via an intermolecular Suzuki-Miyaura C-C coupling and an intramolecular C-O coupling.