Palladium-catalyzed direct construction of oxazoline-containing polycyclic scaffolds via tandem addition/cyclization of nitriles and arylboronic acids

Abstract

An efficient construction of oxazoline-containing polycyclic scaffolds through a Pd-catalyzed addition/cyclization of (hetero)arene tethered O-acyl cyanohydrin units and arylboronic acids is described.

Selective synthesis of functionalized α,β-multi-substituted α-amino cyclopentanones via an α-iminol rearrangement enabled by Pd-catalyzed addition of arylboronic acids to nitriles

“…According to these results and other previous reports, 4,11 a possible mechanism is proposed in Scheme 6. At first, the transmetalation between arylboronic acid and Pd( ii ) catalyst A produces arylpalladium species B .…”

“…carbonyl group) to produce azaheterocyclic products (Scheme 1a). 3,4 In this context, the development of new synthetic strategies through TM-catalyzed addition of boronic acids to nitriles coupled with diverse transformations of the resultant ketimine intermediates to construct high-value added compounds is attractive and highly demanded.…”

Metal-catalyzed reactions of organic nitriles and boronic acids to access diverse functionality

“…In 2021 a Pd( ii )-catalyzed construction of oxazolin-containing polycyclic scaffolds ( 146 and 148 ) was developed by Liao and co-workers via a tandem addition/cyclization of (hetero)arene tethered O -acyl cyanohydrin units ( 145 and 147 ) with arylboronic acids (Scheme 73). 100 This is an important N-heterocyclic framework that is found in some biologically active compounds. In this protocol, different polycyclic quinoxazoline derivatives are prepared with good efficiencies under mild conditions.…”

“…Based on control experiments a plausible mechanism for the synthesis of polycyclic oxazoline is proposed (Scheme 74). 100 Initially, the arylpalladium intermediate ( B ) is formed via a transmetalation of catalyst ( A ) with arylboronic acid. Next, coordination of this intermediate ( B ) with the cyano group forms intermediate ( C ), which is followed by carbopalladation to give the imine intermediate ( D ).…”