Tandem Manganese Catalysis for the Chemo-, Regio-, and Stereoselective Hydroboration of Terminal Alkynes: In Situ Precatalyst Activation as a Key to Enhanced Chemoselectivity

04 December 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The manganese(II) complex [Mn(iPrPNP)Cl2] (iPrPNP = bis(diisopropylphosphine)pyridyl)) was found to catalyze the stereo- and regioselective hydroboration of terminal alkynes employing HBPin (pinacolborane). In the absence of in situ activators, mixtures of alkynylboronate and E-alkenylboronate esters were formed, whereas when NaHBEt3 was employed as in situ activator, E-alkenylboronate esters were exclusively accessed. Mechanistic studies revealed a tan-dem C-H borylation / semihydrogenation as the pathway accounting for the formation of the products. Stoichiometric reactions hint toward reaction of a Mn-H active species with the terminal alkyne as the catalyst entry pathway to the cycle, whereas reaction with HBPin led to catalyst deactivation.


Chemoselectivity control
Tandem catalysis
Sustainable synthesis

Supplementary materials

Supporting Information
The Supporting Information is available free of charge. Complete experimental details, characterization data, NMR spectroscopic data (PDF)


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.