Direct and practical Gilman-Speeter synthesis of 3,4-trisubstituted β-lactams via the Thorpe-Ingold effect
A highly efficient Gilman-Speeter synthesis of 3,4-trisubstituted β-lactams possessing a 4-aryl substituent is described, employing a direct, uncatalyzed Mannich reaction between TMS imines and TMS ketene acetals. The process avoids cryogenic conditions, making it more amenable to process-scale use than related methods for β-lactam synthesis. A Gilman-Speeter diastereoselective version using a sulfinyl imine and leading to homochiral sulfinyl β-aminoester is also presented.
Preparation of β-amino esters and β-lactams from nitriles via aldimine-borane complexes
A one-pot synthesis of β-amino esters has been achieved in 59-75% yield from aromatic and aliphatic nitriles via the condensation of the corresponding non-enolizable and enolizable aldimine-triethylborane complexes, respectively with methyl trimethylsilyl ketene acetals. Grignard-mediated lactamization of the intermediate β-amino esters provides the corresponding β-lactams in the same pot in 58-74% overall yield. Tha japan Institute of Heterocyclic chemistry.
Ramachandran, P. Veeraraghavan,Biswas, Debanjan,Chen, Guang-Ming
experimental part
p. 1423 - 1433
(2011/05/05)
Fibrinogen receptor antagonist and pharmaceutical compositions comprising the same
Compounds of the following general formula (I) and pharmaceutically acceptable salts thereof.
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(2008/06/13)
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