The acid-mediated ring opening reactions of α-aryl-lactams

Abstract

4-Aryl-azetidin-2-ones (β-lactams) undergo ring opening with triflic acid to give cinnamamides which, in benzene, react further to give 3-aryl-3-phenyl-propionamides. Prolonged reaction times in benzene give 3,3-diphenyl-propionamide via an aryl/phenyl exchange. Lactams of ring size 7 and higher also ring open, but only 7- and 8-membered rings give pure diphenylalkylamides. AlCl(3) only ring opens the 4-aryl-azetidinones.

One-Pot Reductive Allylation of Amides by Using a Combination of Titanium Hydride and an Allylzinc Reagent: Application to a Total Synthesis of (–)-Castoramine

“…for C 13 H 18 NO 204.1383 [M+H + ], found 204.1381. Spectroscopic data were identical with those previously reported 14.…”

Metal-free hydroarylation of the side chain carbon–carbon double bond of 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles in triflic acid

“…The most efficient catalysts for these purposes are complexes of the transition metals Pt [28], Au [29], Ru [30], Rh [31–33], Ni [34], Pd [35], and Pd/Ag [36]. However, a metal-free hydroarylation variant of C=C bonds under the action of Brønsted or Lewis superacids has been developed [37–38] and we were able to extend the scope of this reaction [24–25]. …”

Non-transpeptidase binding arylthioether β-lactams active against Mycobacterium tuberculosis and Moraxella catarrhalis

“…14-17 Recently, β-lactam ring opening under acidic conditions has been demonstrated with lactams having an aryl substituent at C4. 18 In addition, α,β-unsaturated amides have been reported as transglutaminase inhibitors, based on their function as Michael acceptors to the nucleophilic sulfur in the active site. 19 Regardless of the mechanism, the presence of a EWG will increase the reactivity of the lactam.…”