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Synfacts 2014; 10(1): 0063
DOI: 10.1055/s-0033-1340457
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Formal Insertion of Diazo Esters into Aryl–CHO Bonds

Contributor(s):
Hisashi Yamamoto
,
Mahiuddin Baidya
Gao L, Kang BC, Ryu DH * Sungkyunkwan University, Suwon, Korea
Catalytic Asymmetric Insertion of Diazoesters into Aryl–CHO Bonds: Highly Enantioselective Construction of Chiral All-Carbon Quaternary Centers.

J. Am. Chem. Soc. 2013;
135: 14556-14559
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Publication History

Publication Date:
13 December 2013 (online)

 
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Key words

oxazaborolidines - diazo esters - Roskamp reaction

Significance

The authors developed an oxazaborolidinium ion catalyzed asymmetric formal C–C bond insertion of diazo esters into aryl–CHO bonds to give functionalized acyclic all-carbon α-quaternary aldehydes in good yields (up to 83%) and excellent enantioselectivities (up to 99%). The products were transformed into synthetically useful α- and β-amino esters with ease.


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Comment

Contrary to the Roskamp reaction, the 1,2-aryl shift is preferred over the 1,2-hydride shift. It is the first catalytic asymmetric report of such a reaction. A variety of diazo esters and aldehydes were explored emphasizing synthetic flexibility. However, the regioselectivities are rather moderate (up to 88:12). Recently, Feng and co-workers reported a similar 1,2-aryl shift for the asymmetric homologation of α-keto esters ­(Angew. Chem. Int. Ed. 2013, 52, 10883).


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