Transition‐Metal‐Free Alkoxycarbonylation of Aryl Halides

Abstract

Transitions: The title reaction has been developed for the synthesis of a variety of tert-butyl benzoates by employing 1,10-phenanthroline as an additive. Various functional groups were tolerated and heteroaryl iodides were also suitable substrates. Preliminary mechanism studies were conducted and indicate the participation of radical intermediates.

Free‐Radical Multicomponent Processes

“…One-carbon homologation of aryl halides (e.g., 92) leading to esters (e.g., 93) has also been reported using a combination of t-BuOK and a bidentate nitrogen ligand (1,10-phenanthroline) (4). Relatively good yields of esters are obtained under high pressure of CO [63]. The proposed mechanism involves SET from the strong base to the aryl iodide 92, generating an aryl radical that is trapped by CO to furnish the acyl radical.…”

Controlled Light‐Mediated Preparation of Gold Nanoparticles by a Norrish Type I Reaction of Photoactive Polymers

“…To exclude AuNP generation by reduction with the solvent upon irradiation, we ran an experiment in the absence of polymer 4 with light. [38] We currently disregard formation of polyacids by air oxidation of the acyl radicals to the corresponding peracids followed by reduction as suggested by Scaiano et al, [21] since AuNP formation has to be conducted under argon atmosphere (O 2 is detrimental to this process). Note that complete photocleavage of the HAK groups should occur in af ew minutes,i fone considers at riplet lifetime in the range of 0.37-13 ns and aq uantum yield of 0.29-0.67 depending on the substituents at the para position of aryl group.…”

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

“…The use of a flow process resulted more efficient, versatile and sustainable compared to batch. Moreover, this operationally simple procedure complements well with the already available strategies for the preparation of tert -butyl esters, avoiding the use of inflammable and explosive gaseous isobutylene [35], the use of harsh conditions [36], the use of peroxides [37], the use of toxic gas such as CO or transition metals [38–42]. The flow process, for the direct C- tert -butoxycarbonylation of organolithiums, has been optimized in a green solvent such as 2-MeTHF by a precise control of the residence time, and without using cryogenic conditions (Scheme 6).…”