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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: bluebunny2020 on February 24, 2020, 11:11:06 PM

Title: Demurcuration Radical Mechanism
Post by: bluebunny2020 on February 24, 2020, 11:11:06 PM

Anyone know the mechanism for this process? I've looked all over the internet but haven't found anything on how NaBH4 actually removes Hg-OAc

Thanks ahead of time!

Title: Re: Demurcuration Radical Mechanism
Post by: hollytara on February 25, 2020, 04:44:03 PM

The mechanism I have seen has these steps:

Hydride ion (H-) from borohydride displaces the acetate on mercury to form R-Hg-H

Homolytic cleavage of R-Hg bond.

Transfer of H radical to carbon radical from Hg-H to form R-H bond (C-H) and free mercury metal. 

This was established by Whitesides back in 1970. 

https://pubs.acs.org/doi/pdf/10.1021/ja00725a039 

Title: Re: Demurcuration Radical Mechanism
Post by: ch3mist on February 27, 2020, 05:00:47 PM

Pasto and Gontarz published a similar study on the reduction of -Hg(OAc) with borohydride a year before Whitesides. Same mechanism as the one described above.

JACS 1969, 91(3), 719-721
https://pubs.acs.org/doi/pdf/10.1021/ja01031a036