A Rhodium‐Catalyzed Cascade Cyclization: Direct Synthesis of N‐Substituted Phthalimides from Isocyanates and Benzoic Acids

Abstract

A rhodiumA C H T U N G T R E N N U N G (III)-catalyzed amidation between benzoic acids and isocyanates via direct functionalization of an ortho C À H bond followed by intramolecular cyclization is described. This cascade cyclization affords N-substituted phthalimides in one step in 26-91% yields. The reaction is highly atom-economical, since no theoretical waste except for water is generated in the reaction.

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

“…116 The reaction employs readily available inputs and proceeds with catalytic [Cp*RhCl 2 ] 2 and stoichiometric NaOAc in the absence of a silver halide abstracting agent. A variety of functionalized benzoic acids bearing both electron-donating and electron-withdrawing substituents were coupled efficiently, including diversifiable groups such as chloro and NHBoc.…”

Versatile and Sustainable Synthesis of Cyclic Imides from Dicarboxylic Acids and Amines by Nb2O5 as a Base‐Tolerant Heterogeneous Lewis Acid Catalyst

“…The typical methods [1,[3][4][5] are the dehydrative condensation of an anhydride with an amine at high temperatures or in the presence of an excess amount of promoter (Lewis acid, base, dehydrating agent, or ionic liquids) [3] and the cyclization of an amic acid with the help of acidic reagents, [4] which suffer from low atom efficiency and production of byproducts. Although new synthetic routes from nitriles, [6] halides, [7] alkyne, [8] pyridin-2-ylmethylamines, [9] aryl boronic acids, [10] aliphatic amides, [11, 12a] cyclic amines, [12b] isocyanates, [13] and phthalimide [14] using transition-metal catalysis (carbonylation, oxidation, etc.) [6][7][8][9][10][11][12][13] or excess amounts of I(III) oxidant [14] have been developed, these homogeneous catalytic methods have drawbacks of narrow substrate scope, needs of various additives or toxic reagents [a]…”

Rhodium(III)‐Catalyzed in situ Oxidizing Directing Group‐ Assisted CH Bond Activation and Olefination: A Route to 2‐Vinylanilines

“…The results are in agreement with those in Table 1 and support the proposed mechanism in Scheme . It is noteworthy that a HOAc/OAc − buffer medium is necessary for the catalytic reaction to proceed and RhCp*(OAc) 2 , generated from [RhCp*Cl 2 ] 2 and NaOAc, is plausibly the active catalyst 10a,b. The NaCl precipitation appears to be the driving force for the generation of RhCp*(OAc) 2 7h,j.…”