Synlett 2009(6): 994-998  
DOI: 10.1055/s-0028-1088198
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Rhodium-Catalyzed Asymmetric 1,4-Addition of Heteroaryl Cyclic Triolborate to α,β-Unsaturated Carbonyl Compounds

Xiao-Qiang Yu, Yasunori Yamamoto*, Norio Miyaura*
Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
Fax: +81(11)7066561; e-Mail: yasuyama@eng.hokudai.ac.jp; e-Mail: miyaura@eng.hokudai.ac.jp;
Further Information

Publication History

Received 16 December 2008
Publication Date:
16 March 2009 (online)

Abstract

Rhodium-catalyzed asymmetric 1,4-additions of electron-deficient heteroaryl groups to α,β-unsaturated carbonyl compounds were established. The reaction resulted in very low yields due to competitive C-B bond cleavage when arylboronic acids, their pinacol esters, or potassium trifluoroborates were used. However, the corresponding lithium heteroaryl(triol)borates afforded 1,4-adducts with high enantioselectivities up to 97% in the presence of a rhodium(I) catalyst chelated with a chiral BINAP or BIPAM ligand.