Synlett 2021; 32(12): 1179-1186
DOI: 10.1055/a-1463-9527
synpacts

Cooperative Hydrogen Atom Transfer: From Theory to Applications

Padmanabha V. Kattamuri
,
This work was financially supported by the Cancer Prevention and Research Institute of Texas (RR190025) and startup funds from Rice University.


Dedicated with respect and admiration to Prof. Harry B. Gray on the occasion of his 85th birthday

Abstract

Hydrogen atom transfer (HAT) is one of the fundamental transformations of organic chemistry, allowing the interconversion of open- and closed-shell species through the concerted movement of a proton and an electron. Although the value of this transformation is well appreciated in isolation, with it being used for homolytic C–H activation via abstractive HAT and radical reduction via donative HAT, cooperative HAT (cHAT) reactions, in which two hydrogen atoms are removed or donated to vicinal reaction centers in succession through radical intermediates, are comparatively unknown outside of the mechanism of desaturase enzymes. This tandem reaction scheme has important ramifications in the thermochemistry of each HAT, with the bond dissociation energy (BDE) of the C–H bond adjacent to the radical center being significantly lowered relative to that of the parent alkane, allowing each HAT to be performed by different species. Herein, we discuss the thermodynamic basis of this bond strength differential in cHAT and demonstrate its use as a design principle in organic chemistry for both dehydrogenative (application 1) and hydrogenative (application 2) reactions. We hope that this overview will highlight the exciting reactivity that is possible with cHAT and inspire further developments with this mechanistic approach.

1 Introduction and Theory

2 Application: Dehydrogenative Transformations

3 Application: Alkene Hydrogenation

4 Future Applications of cHAT



Publication History

Received: 10 March 2021

Accepted after revision: 24 March 2021

Accepted Manuscript online:
24 March 2021

Article published online:
20 April 2021

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