Copper-Catalyzed Stereospecific Transformations of Alkylboronic Esters
Ningxin Xu, Hao Liang, and James P. Morken*
*Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States,
Email: morken
bc.edu
N. Xu, H. Liang, J. P. Morken, J. Am. Chem. Soc., 2022, 144, 11546-11552.
DOI: 10.1021/jacs.2c04037
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Abstract
Boron "ate" complexes derived from pinacol boronic esters and tert-butyl lithium undergo stereospecific transmetalation to copper cyanide, followed by coupling with alkynyl bromides, allyl halides, propargylic halides, β-haloenones, hydroxylamine esters, and acyl chlorides. This simple transformation converts primary and secondary alkylboronic esters to a wide array of useful compounds.
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proposed reaction pathway
Details
The document discusses a study on copper-catalyzed stereospecific transformations of alkylboronic esters, highlighting a novel method for cross-coupling these esters with various electrophiles. The research, conducted by Ningxin Xu, Hao Liang, and James P. Morken, demonstrates that boron "ate" complexes derived from pinacol boronic esters and tert-butyl lithium can undergo stereospecific transmetalation to copper cyanide, followed by coupling with alkynyl bromides, allyl halides, propargylic halides, β-haloenones, hydroxylamine esters, and acyl chlorides. This method allows for the conversion of primary and secondary alkylboronic esters into a wide array of synthetically useful compounds. The study also explores the use of different activators and catalysts, finding that tert-butyl lithium and CuCN are particularly effective. The reactions maintain high enantiospecificity and yield, making this approach valuable for asymmetric synthesis. Additionally, the method shows compatibility with various functional groups and can be applied to complex, highly oxygenated substrates. The research provides a significant advancement in the field of organoboron chemistry, offering a versatile and efficient strategy for the stereospecific functionalization of alkylboronic esters.
Key Words
alkynylation, allylation, allenes
ID: J48-Y2022
