Manganese-catalyzed [2+2+2] Cycloaddition Reactions

02 September 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

We report the cyclotrimerization reactions of triynes using Mn(I) complexes derived from MnBr(CO)5 and phosphine ligands such as 1,1-bis(diphenylphosphino)methane (dppm). These reactions are driven by irradiation under mild conditions (30-80 °C) without the need of additional photoinitiators. Our catalytic screening revealed that counter anions and ligands significantly influence the process. This method accommodates a broad range of functionalities in the substrates, including alkyl, aryl, Bpin, TMS, PPh2, pyridyl, and thienyl moieties, without notable interference in the transformation. Additionally, this method enables reactions with oligoalkynes like (un)substituted hexaynes, producing two-fold cyclization products in excellent yields. Under stoichiometric conditions, the cyclization of diynes with phosphaalkynes results in the first photochemical synthesis of phosphinines. Experimental and theoretical mechanistic studies indicate that the dissociation of the diphosphine ligand precedes the involvement of the Mn-carbonyl species in the catalytic cycle. The ligand plays a crucial role in stabilizing the catalyst during the transformation and preventing the formation of unreactive cluster species.

Keywords

Manganese
[2+2+2] Cycloaddition
Triynes
Arenes
Reaction mechanism
Phosphinines

Supplementary materials

Title
Description
Actions
Title
Supporting Information for Manuscript
Description
File contains experimental data including synthesis of substrates, catalytic experiments, product characterization, mechanistic investigations and data from computational calculations.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.