Manganese-salen catalyzed oxidative benzylic chlorination

  • Sheuli Sasmal
  • Sujoy Rana
  • Goutam Kumar LahiriEmail author
  • Debabrata MaitiEmail author
Regular Article


Metalloporphyrins are well-known to serve as the model for mimicking reactivities exhibited by cytochrome P450 hydroxylase. Recent developments on selective C–H halogenation using Mn-porphyrins provided the way for understanding the reactivity as well as mechanism of different halogenase enzymes. In this report, we demonstrated a method for benzylic C–H chlorination using easily prepared Mn(salen) complex as the catalyst, which shows a complementary reactivity of Mn-porphyrins. Here, NaOCl has been used as a chlorinating source as well as the oxidant. Efforts towards understanding the mechanism suggested the formation of the high-valent Mn(V)=O species which is believed to be the key intermediate to conduct this transformation.

Graphical abstract

SYNOPSIS Mn(salen)-catalyzed selective benzylic chlorination protocol has been developed using aqueous NaOCl solution. Reactions proceeded efficiently at room temperature and displayed good functional group tolerance. The mechanistic investigation demonstrated that \(\hbox {Mn}(\hbox {V}){=}\hbox {O}\) species is likely to be the key intermediate which is responsible to generate benzylic radical. EPR and ESI-MS studies confirmed the in situ formation of Mn(IV)-species.


High-valent manganese salen hypochlorite benzylic chlorination 



This activity is supported by SERB, India (EMR/2015/000164). Financial support has been received from CSIR-India (Fellowship to S.R.).

Supplementary material

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Supplementary material 1 (pdf 1245 KB)


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Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  1. 1.Department of ChemistryIndian Institute of Technology BombayPowai, MumbaiIndia

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