Benzene-1,3,5-triyl Triformate (TFBen)-Promoted Palladium-Catalyzed Carbonylative Synthesis of 2-Oxo-2,5-dihydropyrroles from Propargyl Amines

Abstract

In this letter, we developed a palladiumcatalyzed procedure for the cyclocarbonylation of propargyl amines. Benzene-1,3,5-triyl triformate (TFBen) has been explored as the CO source and also as the key promotor. Various substituted 2-oxo-dihydropyrroles were produced in a facile manner in good yields (up to 90%).

Palladium‐Catalyzed Carbonylative Synthesis of 1,5‐Dihydro‐2H‐pyrrol‐2‐ones from Propargyl Amines and Benzyl Chlorides

“…Notably, the transformation features the trans ‐chlorometalation of the triple bond of propargyl amines. Recently, our group realized a palladium‐catalyzed cyclocarbonylation of propargyl amines with TFBen (benzene‐1,3,5‐triyl triformate) to access 2‐oxo‐2,5‐dihydropyrroles [10] . In this reaction, TFBen [11] was employed as the CO source and the key promoter as well.…”

“…On the basis of previous reports [10][11][12] and above control experiments, a plausible mechanism for the palladium-catalyzed double carbonylation of propargyl amines and benzyl chlorides has been proposed (Scheme 4). Initially, the active Pd(0) catalyst, formed from Pd(II) and DPPF, can react with benzyl chloride 2 a to give the Pd(II) intermediate A via oxidative addition.…”

“…Recently, our group realized a palladium-catalyzed cyclocarbonylation of propargyl amines with TFBen (benzene-1,3,5-triyl triformate) to access 2-oxo-2,5dihydropyrroles. [10] In this reaction, TFBen [11] was employed as the CO source and the key promoter as well. Herein, we now disclose a palladium-catalyzed double carbonylative cyclization of propargyl amines, benzyl chlorides, and TFBen for the expedite construction of 1,5-dihydro-2H-pyrrol-2-one scaffolds.…”

Palladium‐Catalyzed Carbonylative Synthesis of 1‐Acyl‐1,5‐dihydro‐2H‐pyrrol‐2‐ones from Propargyl Amines and Acid Chlorides

“…On the basis of control experiments and previous reports, [11,12] a plausible mechanism is proposed for a palladium-catalyzed carbonylative cyclization of propargyl amines and alkoyl chlorides (Scheme 5). Initially, the active (DPPF)Pd(0) species is generated from the reaction of Pd(II) with DPPF.…”

Carboxyboronate as a Versatile In Situ CO Surrogate in Palladium‐Catalyzed Carbonylative Transformations

“…The Wu group reported benzene‐1,3,5‐triyl triformate (TFBen) as a suitable in situ CO surrogate for metal‐catalyzed carbonylations [17] . Although examples have been shown to work using the in situ approach, [17a–d] several cases required the use of two‐chamber systems to achieve optimal conversion [17e–h] . A general in situ CO surrogate that is compatible with a wide range of functional groups is still underexplored.…”