Self-addition products from the alkylation of amino acid-derived oxazolidinones: X-ray molecular structures of (2R,4S,1'S)-3-benzoyl-4-[benzoylamino(phenyl)methyl]-4-benzyl-2-phenyl-1,3-oxazolidin-5-one, (2R,4S,1'S)- and (2R,4S,1'R)-3-benzoyl-4-[benzoylamino(phenyl)methyl]-4-isopropyl-2-phenyl-1,3-oxazolidin-5-one

The alkylation of (2R,4S)-3-benzoyl-4-benzyl-2-phenyloxazolidin-5-one 7 with diphenylmethyl bromoacetate proceeded with high diastereoselectivity, and the resulting product was hydrolysed to give [(2'R,4'S)-3'-benzoyl-4'-benzyl-5'-oxo-2'-phenyloxazolidin-4'-yl]acetic acid 9. The self-addition byproduct (2R,4S, 1'S)-3-benzoyl-4-[benzoylamino(phenyl)methyl] -4-benzyl-2-phenyl-1,3-oxazolidin-5-one 11 was also isolated. The structures of compound of 11 and the related self-addition products (2R,4S,1'S and 1'R)-3-benzoyl-4-[benzoylamino(phenyl)methyl]-4-isopropyl-2-phenyl-1,3-oxazolidin-5-one 20 and 21 were determined by X-ray crystallography. The mechanism of formation of the self-addition products is discussed.