Glyceraldehyde acetonide imines

Reactions of nitro compounds with chiral imines have only recently been described. Either chiral 1-phenylethylamine (auxiliary) or the glyceraldehyde acetonide aldehyde was used as the chiral precursors of the imines 66 and 68, which reacted with 3-mesyloxynitropropane to give the 3-nitropyrrolidines dl)-67 and 69, respectively, with good diastereoselectivity. In fact, both products were obtained (almost) exclusively as trans diastereomers with high level of asymmetric induction, but the configurations of the newly formed stereocenters were not determined [44] (Scheme 13). N-Boc imines can be formed... 

Chiral imines have been prepared by reacting (R)-glyceraldehyde acetonide with different co-haloalkylammonium halides. Treatment of the latter with 1.3 equiv. of benzyloxy-, phenoxy- or methoxy acetyl chloride in dichloromethane, in the presence of triethylamine afforded the optically active corresponding (3-lactams (Scheme 38) in high yield and high diastereomeric excess [113]. 

The first pairing, that of a chiral aldehyde with a chiral amine, has been used to further develop the threonine imine method. The use of a threonine-derived imine of (5)-glyceraldehyde acetonide afforded a single diastereomer in 61% yield. ... 

The third pairing, that of an imine with a chiral C-substituent with a chiral ketene, has also been studied. Again, the Evans-Sjogren chiral auxiliary was used as the directing CTOup on the ketene, while imines derived fi-om (/ )-glyceraldehyde acetonide and lactic acid " have been used. 

Our synthesis of the p-lactam nucleus was based upon the highly efficient [2+2] cycloaddition approach.(14) Thus fluoroacetyl chloride is allowed to react with an optically active imine 8, which was obtained by condensation of p-anisidine with (D)-glyceraldehyde acetonide. The product of this cycloaddition reaction, a single diastereomer of 3-fluoro-2-azetidinone 9, was formed in 68% yield in 99% ee.(14) The absolute stereochemistry of this product was confirmed by single-crystal X-ray diffraction studies.(14)... 

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