Recent developments in asymmetric Heck type cyclization reactions for constructions of complex molecules

Abstract

This review summarizes the recent developments in the asymmetric intramolecular Heck reaction and carbometallation-initiated cascade transformations including Ni-catalyzed processes with literature coverage mainly extending from 2016 to 2021.

Nickel-Catalyzed Asymmetric Reductive Dicarbamoylation of Alkenes

“…Intramolecular Heck-type migratory insertion of a pendant olefinic unit into a chiral carbo-metal species constitutes the key enantiodiscriminating step for numerous transition metal-catalyzed asymmetric cyclizations . Although carbamoyl (pseudo)­halides have been known as carbamoylating agents for olefin difunctionalization over decades, the asymmetric variants are still scarce. , In 2008, Takemoto et al.…”

Synergic Palladium Catalysis for Aerobic Oxidative Coupling

“…The regioselectivity of the insertion depends on the electronic and steric characteristics of the alkene and the reaction has two possible pathways, involving either a cationic or neutral palladium complex. [61,62] Specifically, alkenes bearing electron withdrawing groups tend to provide trans β-substituted alkenes whereas alkenes with electron donating groups generate α-substituted alkenes. [63] In contrast, 1,2-disubstituted internal alkenes exhibit low reactivity and provide a mixture of regio-and stereoisomers because the Mizoroki-Heck reaction with internal olefins produces a mixture of (E) and (Z)-products even from a single geometrical isomer.…”

“…In Heck type alkenylation, intra‐ or intermolecular dehydrogenative coupling often allows the formation of C−C, C−N bonds derived from the Pd‐R 1 bond. The regioselectivity of the insertion depends on the electronic and steric characteristics of the alkene and the reaction has two possible pathways, involving either a cationic or neutral palladium complex [61,62] . Specifically, alkenes bearing electron withdrawing groups tend to provide trans β ‐substituted alkenes whereas alkenes with electron donating groups generate α ‐substituted alkenes [63] .…”

Microwave Irradiation: Alternative Heating Process for the Synthesis of Biologically Applicable Chromones, Quinolones, and Their Precursors

“…In 1972, Heck and Nolley reported a halide-olefinic substitution catalyzed by palladium catalysis [ 32 ]. Since then, not only the reaction is generally called Heck reaction but also proved to be suitable in the synthesis of several organic compounds [ 33 , 34 ], including natural products [ 35 ] and more complex molecules [ 36 ].…”