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Synfacts 2007(9): 0942-0942  
DOI: 10.1055/s-2007-968864
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Chlorination of Silyl Enol Ethers

Contributor(s): Hisashi Yamamoto, Joshua N. Payette
S. Hajra*, M. Bhowmick, B. Maji, D. Sinha
Indian Institute of Technology, Kharagpur, India
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Publication History

Publication Date:
23 August 2007 (online)

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Significance

This paper reports a new chiral N-chloroimidodicarbonate ligand L1 which upon complexation to Sm(OTf)3 chlorinates silyl enol ethers to afford α-chloroketones in high yields and moderate ee values. It was found that in several cases the bulky TBDMS group gave consistently higher ee values than the smaller TMS group. The authors postulate that coordination of L1 to the Lewis acid produces the reactive syn-dipole conformer.