Imino esters reaction with silyl ketene acetals

A -Methylephedrine-derived silyl ketene acetals react with imines in the presence of 2 mol equiv. of TiCU to give P-amino esters (equation 15) significant results are summarized in Table 7. With benzyl-ideneaniline the reaction is anti selective (entry 1), while with imino esters that chelate TiCU to give complexes such as (41), the reaction is syn selective (entries 2 and 3), in agreement with the general prin-... 

Amberlyst 15 DRY, a sulfonic cation exchange resin with a large surface area, was found to catalyze the imino aldol reaction of imines with ketene silyl acetals to provide racemic y9-amino esters in yields up to 99% [104]. 

Imino aldol reaction of ketene silyl acetals with the chiral imine derived from tartaric acid 83 in the presence of a cation-exchange resin provided the corresponding /i-amino esters 84 in a good yield and high diastereose-lectivity [68]. The esters 84, thus obtained, were subjected to the Grignard reagent which promoted S-lactam formation. After a sequence of reactions compound 84 was transformed into the ester 85 [68] which in the past was... 

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