Townsend, Tanya M. published the artcileDehydrogenative Synthesis of Carbamates from Formamides and Alcohols Using a Pincer-Supported Iron Catalyst, Related Products of amides-buliding-blocks, the main research area is carbamate preparation; formamide alc dehydrogenative coupling reaction iron catalyst.
The pincer-ligated iron complex (iPrPNP)Fe(H)(CO) [iPrPNP- = N(CH2CH2PiPr2)2-] is an active catalyst for the dehydrogenative synthesis of N-alkyl- and N-aryl-substituted carbamates RNHC(O)OR1 (R = Me, Ph, Bn, etc.; R1 = Me, Cy, Bn, etc.) from formamides RNHCHO and alcs. R1OH. The reaction is compatible with industrially relevant N-alkyl formamides, as well as N-aryl formamides, and 1°, 2°, and benzylic alcs. Mechanistic studies indicate that the first step in the reaction is the dehydrogenation of the formamide to a transient isocyanate by (iPrPNP)Fe(H)(CO). The cyclohexyl isocyanate then reacts with the alc. to generate the carbamate. However, in a competing reaction, the isocyanate such as benzyl isocyanate, cyclohexyl isocyanate undergoes a reversible cycloaddition with (iPrPNP)Fe(H)(CO) to generate an off-cycle species, which is the resting state in catalysis. Stoichiometric experiments indicate that high temperatures are required in catalysis to facilitate the release of the isocyanate from the cycloaddition product I (R2 = Bn, Cy). Several other off-cycle processes that occur in catalysis, such as the 1,2-addition of the formamide or alc. substrate across the Fe-N bond of (iPrPNP)Fe(H)(CO) were also identified. It has already been demonstrated that the transient isocyanate generated from dehydrogenation of the formamide can be trapped with amines to form ureas and, in principle, the isocyanate could also be trapped with thiols to form thiocarbamates. Competition experiments indicate that trapping of the transient isocyanate with cyclohexanamine to produce 1,3-dicyclohexylurea is faster than trapping with an alc. to produce carbamates and thus ureas can be formed selectively in the presence of alcs. In contrast, thiols such as benzylthiol, cyclohexanethiol bind irreversibly to the iron catalyst through 1,2 addition across the Fe-N bond of (iPrPNP)Fe(H)(CO), and it is not possible to produce thiocarbamates. Overall, the mechanistic studies provide general guidelines for facilitating dehydrogenative coupling reactions using (iPrPNP)Fe(H)(CO) and related catalysts.
ACS Catalysis published new progress about 1,2-Addition reaction. 123-39-7 belongs to class amides-buliding-blocks, name is N-Methylformamide, and the molecular formula is C2H5NO, Related Products of amides-buliding-blocks.
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics