HIGHLY EFFICIENT OXAZOLONE-DERIVED REAGENTS FOR BETA-LACTAM FORMATION FROM BETA-AMINO ACIDS
Based on a unique leaving ability of 2-oxazolone moiety, highly efficient reagents have been developed for the formation of β-lactam compounds from β-amino acids including a facile preparation of penam, a basic skeleton of penicillins.
NEW PHOSPHORYLATING AGENTS FOR GENERAL SYNTHESIS OF MIXED PHOSPHATE ESTERS
An effective procedure has been developed for the general synthesis of mixed alkyl or aryl phosphate esters by metal-catalyzed phosphorylation of alcohols with aryl bis(2-oxo-3-oxazolinyl)phosphinate.Among metallic acetylacetonates examined as catalysts, the zirconium complex was the most effective as in activity order of Zr(IV)> Ce(III)> Zn(II)> Mn(III)> Mn(II)-complexes.
Nagamatsu, Tomohisa,Kunieda, Takehisa
p. 2375 - 2378
(2007/10/02)
ACTIVATION OF CARBOXYL GROUPS BY DIPHENYL 2-OXO-3-OXAZOLINYLPHOSPHONATE. FACILE PREPARATION OF VERSATILE REAGENTS, 3-ACYL-2-OXAZOLONES
Synthetic utility of the 2-oxazolone moiety as an excellent new leaving group is described.Based on such a function of the heterocycles, diphenyl 2-oxo-3-oxazolinylphosphonate has been newly introduced as a carboxyl-activating reagent which permits a facile direct preparation of 3-acyl-2-oxazolones and amides including peptides from a wide variety of carboxylic acids.The 3-acyl-2-oxazolides also serve as versatile reactive agents for highly chemoselective acyl-transfer to the nucleophilic species such as amines, alcohols and thiols, providing convenient and high-yield routes to amides, esters and thiol esters under mild conditions.They are also useful intermediates for ketones and alcohols.
A NEW REAGENT FOR ACTIVATING CARBOXYL GROUPS: DIPHENYL 2-OXO-3-OXAZOLINYLPHOSPHONATE
Diphenyl 2-oxo-3-oxazolinylphosphonate serves as a carboxyl-activating reagent to permit a direct preparation of versatile intermediate, 3-acyl-2-oxazolones or a one-step formation of amides from carboxylic acids.