New 3-heterocycle substituted 1,3-thiazolidine-derived 4-spiro-β-lactams with a relative trans-configuration were stereoselectively synthesised by means of a Staudinger ketene-imine reaction between the ketene generated from the (2S,4R)-1,3-thiazolidine-2,3,4-tricarboxylic acid 3-(1,1-dimethylethyl) 4-methyl ester 1 and imines 2b-e. The 1,3-thiazolidine-derived 4-spiro-β-lactams were transformed into the corresponding enantiomerically pure 4-heterocycle substituted azetidine-2,3-diones by means of an oxidative cleavage of the 1,3-thiazolidine ring. The opening of the 1,3-thiazolidine ring was studied under different experimental conditions and a consistent mechanism is proposed.
Stereoselective synthesis of 4-substituted azetidine-2,3-diones by ring opening of 1,3-thiazolidine-derived spiro-beta-lactams / G. Cremonesi, P. Dalla Croce, F. Fontana, C. La Rosa. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 19:5(2008), pp. 554-561. [10.1016/j.tetasy.2008.02.01]
Stereoselective synthesis of 4-substituted azetidine-2,3-diones by ring opening of 1,3-thiazolidine-derived spiro-beta-lactams
G. CremonesiPrimo
;P. Dalla CroceSecondo
;F. FontanaPenultimo
;C. La RosaUltimo
2008
Abstract
New 3-heterocycle substituted 1,3-thiazolidine-derived 4-spiro-β-lactams with a relative trans-configuration were stereoselectively synthesised by means of a Staudinger ketene-imine reaction between the ketene generated from the (2S,4R)-1,3-thiazolidine-2,3,4-tricarboxylic acid 3-(1,1-dimethylethyl) 4-methyl ester 1 and imines 2b-e. The 1,3-thiazolidine-derived 4-spiro-β-lactams were transformed into the corresponding enantiomerically pure 4-heterocycle substituted azetidine-2,3-diones by means of an oxidative cleavage of the 1,3-thiazolidine ring. The opening of the 1,3-thiazolidine ring was studied under different experimental conditions and a consistent mechanism is proposed.
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