Thianthrene for Radical-Mediated Borylation of Alkyl Alcohols

Alkyl thianthrenium salts are generated from alkyl alcohols and thianthrene (1). They are activated by blue light or heat to be converted following a radical pathway into alkyl boronate esters.¹⁾ Various alkyl alcohols activated by trifluoromethanesulfonic anhydride react with 1 to afford thianthrenium salts 2. Alkyl radical 3 species induced by blue light (condition A) or heat (condition B) lead to alkyl boronic acid catechol esters 4. Finally pinacol and organic base are added in a one-pot manner, resulting in desired alkyl boronic acid pinacol esters. Alkyl boronic acid pinacol esters are useful synthetic intermediates for various reactions such as cross-coupling reactions, oxidation, amination and halogenation.²⁾

Related Products

T0184

Thianthrene

T1100

Trifluoromethanesulfonic Anhydride

D0691

Pinacol

B3757

Bis(catecholato)diboron

D3886

4,4'-Dimethoxy-2,2'-bipyridyl

T0424

Triethylamine

References

• 1) Generation of non-stabilized alkyl radicals from thianthrenium salts for C-B and C-C bond formation
  • C. Chen, Z. Wang, H. Lu, Y. Zhao, Z. Shi, Nat. Commun. 2021, 12, 4526.
• 2) Stereospecific functionalizations and transformations of secondary and tertiary boronic esters
  • C. Sandford, V. K. Aggarwal, Chem. Commun. 2017, 53, 5481.

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