engleski

Asymmetric synthesis of β-lactams by chiral ester enolate - imine condensation

Asymmetric cyclocondensation of N, N-bis(silyl)glycinates bearing chiral ester moieties with aldimines is found to proceed with extremely high enantioselectivity to give the corresponding chiral β -lactams in good to high yields. It is found that the E/Z-geometry of the chiral ester-enolate is responsible for cis/trans stereochemistry of the β -lactam formed. Effects of various chiral auxiliaries in the ester-enolates on the enantioselectivity of the reactions are examined.

N, N-bis(silyl)glycinates ; chiral β-lactams ; ester-enolates

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