An application of the PD(O)-catalyzed cyclocarbonylation of primary2-bromoallylamines to the synthesis of E- and Z-3-(hydroxyisopropylidene) azetidin-2-ones, useful precursors to a new class of monocyclic β-lactam antibiotics

Synthesis of Heterocycles via Palladium-Catalyzed Carbonylations

“…23 Interestingly, Brickner and co-workers modified the solvent [using N,N-dimethylformamide (DMF) instead of hexamethylphosphoramide (HMPA)] and made the methodology suitable for unprotected primary 2-bromoallylamines. 24 In addition, Crisp and Meyer succeeded to produce lactams from the corresponding amino vinyl triflates by carrying out the reaction in CH 3 CN. Four-, five-, and six-membered lactams were produced in good to excellent yields.…”

“…Ban and co-workers started from 2-bromo-3-aminopropene derivatives, which in the presence of Pd(OAc) 2 and PPh 3 led to the corresponding α-methylene β-lactams in good yields (Scheme a) . Interestingly, Brickner and co-workers modified the solvent [using N , N -dimethylformamide (DMF) instead of hexamethylphosphoramide (HMPA)] and made the methodology suitable for unprotected primary 2-bromoallylamines . In addition, Crisp and Meyer succeeded to produce lactams from the corresponding amino vinyl triflates by carrying out the reaction in CH 3 CN.…”

“…The methodologies developed by Brickner and Tsuji and their co-workers successfully avoid the use of aziridines in the preparation of lactams, − but the specificity of starting materials limited the scope. Notably, Torii and co-workers succeeded to apply more easily available allyl phosphates and imines for the synthesis of lactams .…”

Synthesis of Heterocycles via Palladium-Catalyzed Oxidative Addition

“…The 2-bromoallylic amines 497 can be cyclized in the presence of a palladium catalyst under carbon monoxide pressure to produce β-lactams (Scheme ) . Thus, the stereoselective reaction of ( Z )- or ( E )-2-bromoallylic amines 497 with Pd(PPh 3 ) 4 in DMF under 1 atm of carbon monoxide gave β-lactams 498 in good yields.…”