Incorporation of molecular nitrogen into organic compounds. 2. Novel lactam synthesis by use of a combination system of carbonylation and nitrogenation

Ruthenium(II)‐Catalyzed CH Activation with Isocyanates: A Versatile Route to Phthalimides

“…However, the limited availability of differently substituted phthalic acids, mostly due to the harsh reaction conditions in their preparation, calls for alternative protocols. Carbonylative cyclizations of prefunctionalized ortho ‐halo benzoic acid derivatives4a–c or ortho ‐dihalo arenes4d, e in the presence of amines are thus attractive routes. Formamides were also utilized to construct the phthalimide scaffold by the action of a palladium catalyst 5.…”

Palladium on Carbon: An Efficient, Heterogeneous and Reusable Catalytic System for Carbonylative Synthesis of N‐Substituted Phthalimides

“…Thereafter 1,2-diiodobenzene reacted with various amine derivatives containing electron-donating or electron-withdrawing groups and in all cases good to excellent yields of expected products were obtained except for 4-nitroaniline (Table 3, entries 6-13). Furthermore, aliphatic amines also provided excellent yields of the desired product (Table 3, entries [14][15][16][17][18][19]. During this study, when the reaction was carried out using an excess of primary amine with diiodobenzene in the absence of DABCO, no yield of desired product was observed, indicating the strong necessity of DABCO as a base additive.…”

“…[19] To the best of our knowledge this is the first heterogeneous protocol wherein o-iodobenzoic acid was explored for synthesis of Nsubstituted phthalimide derivatives (Scheme 3). The developed protocol is applicable for the synthesis of aromatic and aliphatic N-substituted phthalimides from o-bromobenzoic acid furnishing an excellent yield of corresponding product (Table 4, entries 5-7).…”

Carbonylation

“…An exception is the palladium-iron cluster compound Scheme 10.8 [Co) CO,MeOH .. Palladium-catalyzed carbonylation of 2-bromophenyl( alkyl )ketones in the presence of a titanium-isocyanate complex (derived from molecular nitrogen) leads to formation of alkylidenelactams in moderate yield. (468) The reaction (Scheme 10.9) proceeds via an alkylidenelactone intermediate, which can be isolated if required and converted to the lactam in a separate step. Since enolization of the reactant alkylketone is clearly required yields are, not unexpectedly, enhanced by the presence of electron-withdrawing groups (nitrile, sulfonyl) ex to the carbonyl group, but the resulting alkylidene lactams suffer hydration of the exocyclic double bond on aqueous workup.…”