2- oxoimidazolidines

Kinetic resolution of racemic allylic acetates has been accomplished via asymmetric dihydroxylation (p. 1051), and 2-oxoimidazolidine-4-carboxy-lates have been developed as new chiral auxiliaries for the kinetic resolution of amines. Reactions catalyzed by enzymes can be utilized for this kind of resolution. ... 

On the other hand, Doyle et al. have developed methyl 2-oxoimidazolidine-4(carboxylate ligands, containing 2-phenylcyclopropane attached at the 1-iV-acyl site, such as the (4(5),2 (7 ),3 (7 )-HMCPIM) ligand. The resulting dirhodium complex led, for the cyclopropanation of styrene with EDA, to the corresponding cyclopropane with 68% ee and 59% yield, but with almost... 

Mezlocillin Mezlocillin, (2S,5/ ,6/ )-3,3-dimethyl-7-oxo-6-[(R)-2-[(3-methylsulfonyl)-2-oxoimidazolidin-1 -carboxamido] -2-phenylacetamido]-4-thia-1 -azabicyclo[3.2.0]-heptan-2-carboxylic acid (32.1.1.27), is synthesized by acylating ampicillin (32.1.1.16) with 3-chlorocarbonyl-l-methansnlfonyl-2-imidazolidinone (32.1.1.26) in the presence of triethy-lamine. The necessary 3-chlorocarbonyl-l-methansnlfonyl-2-imidazolidinone (32.1.1.26) is synthesized by sulfonating 2-imidazolidinone with methanesulfonyl chloride, which forms... 

Desymmetrization strategy in enantioselective oxonium ylide formation/[l,2]-shift reaction has been reported by Doyle and co-workers.With dirhodium(ii) tetrakis[methyl l-(3-phenylpropanoyl)-2-oxoimidazolidine-4(3 )-carboxylate] [Rh2(43 -MPPIM)4] as the catalyst, up to 88% ee is obtained (Equation (7)). 

A dynamic kinetic resolution was utilized for the highly stereoselective Gabriel synthesis of -amino acids by K. Nunami and co-workers. The substrate, f-butyl-(4S)-1-methyl-3-2-(bromoalkanoyl)-2-oxoimidazolidine-4-carboxylate, smoothly reacted with potassium phthalimide at room temperature to give only one diastereomer in good yield. The removal of the chiral auxiliary afforded an A/-phthaloyl-L- -amino acid. 

Kubo, A., Kubota, H., Takahashi, M., Nunami, K.-i. Dynamic kinetic resolution utilizing 2-oxoimidazolidine-4-carboxylate as a chiral auxiliary stereoselective synthesis of a-amino acids by Gabriel reaction. Tetrahedron Lett. 1996, 37, 4957-4960. 

R = COOMe, X = 4- Bu-Ph Dirhodium(II) Tetrakis[methyl-l-(4-/ 7t-butylbenzoyl)-2-oxoimidazolidine-4(5)-carboxylate]... 

As an example, ferf-butyl (45)-l-methyl-2-oxoimidazolidine-4-carboxylate was used by Nunami and colleagues as a chiral auxiliary for DKR of a-bromo-carboxylic acids. In this case, the nucleophile was a malonic ester enolate and the role of the polarity of the solvent (hexamethylphosphoramide, HMPA) was demonstrated (Scheme 1.2). The alkylated products were further easily converted to chiral a-alkylsuccinic acid derivatives and chiral jS-amino acid derivatives. Moreover, these authors showed that this methodology could be extended to other nucleophiles such as amines." Therefore, the reaction of a diastereomeric mixture of tert-bvAy (45)-l-methyl-2-oxoimidazolidine-4-carb-oxylate with potassium phthalimide predominantly afforded fcrf-butyl (45)-1-methyl-3-((25)-2-(phthaloylamino)propionyl)-2-oxoimidazolidine-4-carboxylate in 90% yield and 94% diastereomeric excess (de). The successive removal of the chiral auxiliary afforded A-phthaloyl-L-alanine. 

The N-deprotected pseudopeptides 1113 and 1115 were cyclized to the corresponding 2-oxoimidazolidines with triphosgene and triethylamine in dry dichloro-methane at 0 °C [796-798],... 

---