Trans diastereoselective synthesis of 3-alkyl substituted β-lactams via the acid chloride-imine reaction of nonactivated acid chlorides

Synthesis of 2-azetidinones substituted quinoline derivative

“…As reported in the literature, cis-isomer shows higher values of the coupling constant than the trans-isomer. 18 The majority of the isolated compounds showed lower values of the coupling constant, confirming the trans-azetidinone. However, a few of them showed a mixture of both, in which the transazetidinones contained small amounts of cis-azetidinone (Table I).…”

Diastereoselective synthesis of trans-trifluoromethyl-β-lactams and α-alkyl-β-trifluoromethyl-β-amino esters

“…A similar complete isomerization was described by B egu e and co-workers with t-BuOK in acetonitrile 44 while Vaccaro and co-workers reported t-BuOK epimerization in THF leading to a 1:4 (cis/trans) mixture of b-lactams. 45 Having established suitable reaction conditions for the synthesis of b-lactam 5d with high diastereoselectivity, the methodology was applied to a series of nonactivated aliphatic acid chlorides 4aeg (Table 2). Whatever the size of the R group, the reaction provided the b-lactams in very similar yields with high diastereoselectivity, greater than 94:6.…”

Kinetics and Mechanism of the Base-Catalyzed Rearrangement and Hydrolysis of Ezetimibe

“…Two sets of signals were found in the 1 H NMR spectrum corresponding to a diastereomeric mixture. Such racemization was previously observed in the literature …”