Palladium-Catalyzed Multicomponent Reaction (MCR) of Propargylic Carbonates with Isocyanides

Abstract

A palladium-catalyzed multicomponent reaction (MCR) of propargylic carbonates with isocyanides is reported. Remarkably, the orderly insertion of isocyanides affords two types of valuable N-heterocyclic products (Z)-6-imino-4,6-dihydro-1H-furo[3,4-b]pyrrol-2-amines and (E)-5-iminopyrrolones in high yields. Systematic analysis of the reaction conditions indicates that the selectivity of these N-heterocyclic products can be controlled by ligands and temperature.

Exploring the Reactivity of Propargylic Ester: Acyloxy and Acyl Migratory Rearrangement Relay Enabled by Formal Double Isocyanide Insertion

“…In an oxygen isotope‐labeling experiment, [O 18 ]‐ 1 a and 2 a was used to afford [O 18 ]‐ 3 a , suggesting a migratory step occurred (Scheme 2, eq 3). In addition, another isotope experiment also demonstrated that no O 18 was incorporated into the resulting product 3 a when H 2 O 18 served as the third component (Scheme 2, eq 4), thus ruling out the possibility of water as oxygen source [21] …”

“…In addition, another isotope experiment also demonstrated that no O 18 was incorporated into the resulting product 3 a when H 2 O 18 served as the third component (Scheme 2, eq 4), thus ruling out the possibility of water as oxygen source. [21] In the presence of optimal conditions, a gram-scale synthesis was conducted with propargylic pivalate 1 a (3 mmol, 0.86 g) and isocyanide 2 a (6 mmol, 0.78 g), affording 3 a in 63% yield (1.04 g) (Scheme 3, eq 1). Treatment of 3 a with Pd/C in ethanol at room temperature for 8 h led to double bond reduction and delivered compound 9 in 62% yield (Scheme 3, eq 2).…”

Recent Advances on Pyrrole Synthesis through Different Annulation Modes

“…Using isocyanide as C1N1 unit, Jiang and Wu et al [128] reported a palladium-catalyzed multicomponent reaction for the synthesis of pyrrole derivatives from propargylic carbonates and isocyanides (Scheme 91). This reaction Scheme 91 Palladium-promoted cyclization between propargylic carbonates and isocyanides started with the formation of allene intermediate, which went through isocyanide insertion and three consecutive addition steps to produce key intermediate for final cyclization.…”

Transition-Metal-Catalyzed Diarylation of Isocyanides with Triarylbismuthines for the Selective Synthesis of Imine Derivatives

“…Recently, we developed novel palladium-catalyzed diarylation reactions of isocyanides 2 [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ] using triarylbismuthines 1 and tetraarylleads 4 ( Scheme 1 ). The use of BiAr 3 1 result in α -diimines 3 being selectively obtained ( Scheme 1 a) [ 42 ].…”