Hydrocarbamoylation

Matsuda et al. applied aryl isocyanates as acceptors in reductive couplings to methyl acrylate (Scheme 44) [77]. The cationic Rh complex [Rh(COD) P(OPh)3 2]OTf (1 mol%) and Et2MeSiH (200 mol%) catalyze the reaction in refluxing CH2C12 to provide products of hydrocarbamoylation,... 

Methoxytetralin, substituted naphthalene reduction to tetralin, 132-133 Methyl-2-(phenylcarbamoyl)butanoate, a,-unsaturated ester hydrocarbamoylation, 134 4-Methylbenzyl chloride [reductive... 

Apparent Hydrocarbamoylation to a, -Enoates and Mannich-Type Coupling... 

Bearing this idea in mind, the authors synthesized a class of chiral diaminophosphine oxide ligands and tested them in the Ni-catalyzed intramolecular asymmetric hydrocarbamoylation reactions of formamides 38 with AlMCa as the other metal catalyst (Scheme 8.18). The combination of [Ni(cod)2] and (i ,i )-L3 gave the optimal catalytic activity. Substrates with various substitution patterns were converted smoothly to their corresponding pyrrolidinones 39 in up to 98% yield and 95% ee under very mild conditions. 

Scheme 8.18 Ni-catalyzed asymmetric hydrocarbamoylation reactions reported by Cramer.

Ni(0)/AlMe3-catalysed asymmetric intramolecular hydrocarbamoylation reactions can be carried out by using cbiral ligand 41, providing pyrrolidones in bigb yields and enantioselectivities (Scheme 14.73). It is believed that a Ni-Al bimetallic complex supported by tbe chiral ligand (42) is formed and this bimetallic species has superior reactivity. ... 

The new complex (166), generated from the corresponding diaminophosphine oxide and Mc3 Al, has been employed as a chiral ligand for the Ni(0)-catalysed C-H activation of A-homoallyl formamide (163), which provides pyrrolidones (165) via intramolecular hydrocarbamoylation (164) in <94%... 

Hiyama, Nakao and coworkers have demonstrated the efficient inter-molecular hydrocarbamoylation reactions of alkynes and 1,3-dienes with dialkyformamides, catalyzed by a nickel/Lewis acid combination, to allow direct atom-efficient access to a range of unsaturated amides. Intra-molecular hydrocarbamoylation of olefins also proceeds by the binary catalysis to give lactam derivatives (Scheme 5.38). ... 

In 2013, Carreira and coworkers presented an attractive strategy for the synthesis of chiral pyrrolidones via ruthenium-catalyzed intramolecular hydrocar-bamoylation of allylic formamides under CO atmosphere (Eq. (7.2)) [7]. A formal ruthenium-catalyzed intramolecular insertion into the formamide C-H bond and concomitant C-C bond formation by olefin hydrocarbamoylation were involved in the reaction, which made the reaction complete atom economy. The cycliza-tion performed with a broad substrate scope. More interestingly, even homoallylic and bis-homoallylic formamide substrates were used, the reactions afforded five-membered nitrogen-containing heterocycles only. 

A ruthenium-catalyzed intramolecular olefin hydrocarbamoylation for the regiodivergent synthesis of indolin-2-ones and 3,4 dihydroquinolin-2-ones was disclosed by Chang and coworkers (Eq. (7.3)) [8]. The reactions underwent smoothly without requiring external CO atmosphere. In the presence of combined catalysts of Ru3(CO)i2/Bu4NI, a 5-exo-type cyclization proceeds favorably to form indolin-2-ones as a major product in good to excellent yields in DMSO/toluene cosolvent (catalytic system A). When the reaction was conducted in the absence of halide additives in NAf-diniethylacetamide (DMA)/PhCl (catalytic system B), 3,4-dihydroquinolin-2-ones were obtained in major in moderate to high yields via a 6-endo cyclization process. An excellent level of regioselectivity was observed with a variety of substrates to deliver 5-exo- or 6-endo-cyclized lactams. 

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