Vicinal C-Functionalization of Alkenes. Pd/Light-Induced Multicomponent Coupling Reactions Leading to Functionalized Esters and Lactones

Abstract

Under photoirradiation conditions using a xenon light, and in the presence of PdCl(2)(PPh(3))(2) as a catalyst, four-component coupling reactions comprising of α-substituted iodoalkanes, alkenes, carbon monoxide, and alcohols proceeded smoothly to give functionalized esters in good yields. When alkenyl alcohols were used as acceptor alkenes, three-component coupling reactions accompanied by intramolecular esterification proceeded to give lactones in good yields. The present reaction system represents the vicinal C-functionalization of alkenes.

Free‐Radical Multicomponent Processes

“…For instance, addition of octyl iodide 85 onto CO in the presence of ethanol was shown to provide in 16 h the desired ester 94 in 87% yield (Scheme 14.22, (1)) [67]. When the Pd catalyst was omitted, 94 was obtained in only 50% yield after 50 h. With α-iodoester 4, the generated electrophilic radical can add to an electron-rich olefin to generate a new nucleophilic radical that is then trapped by carbon monoxide [68]. Diester 96 is finally produced in high yield (2).…”

Pd/Light‐Accelerated Atom‐Transfer Carbonylation of Alkyl Iodides: Applications in Multicomponent Coupling Processes Leading to Functionalized Carboxylic Acid Derivatives

“…Consequently, we reported a series of three-or four-component coupling reactions to afford a wide range of carboxylic acid derivatives. [16] Herein, we report the full scope of the Pd/hn-induced ATC reaction for primary, secondary, and tertiary alkyl iodides, which can provide useful synthetic methods to prepare a variety of carboxylic acid derivatives. Interestingly, more than two decades ago, Kubiak and co-workers reported that [ 6 ] 2 is an isolable Pd dimer that, under photoirradiation, is likely to produce a pair of Pd radicals.…”

Synthesis of Carbamoylacetates from α-Iodoacetate, CO, and Amines under Pd/Light Combined Conditions

“…7 As such an example, the reaction of α-substituted iodoalkanes, CO, and alkenyl alcohols gave good yields of functionalized lactones. 8 Interestingly, however, in a similar reaction using an alkenylamine, we found that the envisioned lactam was obtained only in a low yield, and the carbamoylacetate was formed as a principal product. This led us to investigate the carbonylation reaction, and herein we report a novel synthesis of carbamoylacetates by the three-component coupling reactions comprising α-iodoacetate, CO, and amines (Scheme 1, equation 2).…”