Background

Manganese chloride (MnCl₃) is synthetically useful in alkene dihalogenation. However, MnCl₃, itself, is unable to be isolated, presumably due to its poor stability, thus requiring solutions to be prepared and used immediately, oftentimes with ill-defined speciation prior to its use. MnCl₃ stable sources prepared through existing in situ means (electrochemical and chemical) require storage at -30 °C, result in a lack of precisely known stoichiometry, cannot be separated from soluble reaction byproducts, and/or require the use of acid, the latter of which may preclude their use in certain reactions.

Technology Overview

This University at Buffalo invention provides a method for preparing stable sources of MnCl₃ that can be carried out open to air using reagent-grade solvents. One such isolated MnCl₃ complex resulting from this method is bench-stable even when stored in transparent glass vials and can be handled open to air with no apparent impacts on its desired reactivity. This complex has been used in a variety of coordination reactions to prepare several new and known Mn(III) compounds. When explored for its practical application in dihalogenation, specifically dichlorination, of alkenes, this complex demonstrated an ability to be used across a wide range of both substrates and solvents, open to the air, and resulted in appreciable and/or high yields of product. In one example, when this complex was used with 1-phenyl cyclohexane as the substrate, it yielded a substantially higher dr for the anti-dichloride product than that resulting from the electrocatalytic Mn(III) chloride generation (>19:1 vs. 8:1, respectively). Further, the chlorine atom transfer step resulting from the use of this MnCl₃ complex appears to be accelerated by light.

Further Details:

2022 J. Am. Chem. Soc. (https://pubs.acs.org/doi/10.1021/jacs.2c08509)

Stage of Development

Gram-scale synthesis of the MnCl₃ complex.

Benefits

Ease of preparation
Bench stable
Able to be prepared and used open to air
Ability to be used with acid labile groups
Good chemoselectivity
High stereoselectivity
Broad versatility across substrates and solvents
Light-accelerated halogen atom transfer

Applications

Coordination chemistry
Dihalogenation of alkenes

Opportunity

Available for licensing or collaboration.

Manganese(III) Complexes for Coordination Chemistry & Dihalogenation of Alkenes

Patents

IP Status

Seeking