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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 15, Number 9
BKCSDE 15(9)
September 20, 1994 

 
Title
Asymmetric [2,3]-Wittig Rearrangements in the Presence of Sparteine Derivatives
Author
Jahyo Kang, Won Oh Cho, Hyung Geun Cho, Hee Jin Oh
Keywords
Abstract
Asymmetric [2,3]-Wittig rearrangements of allyl propargyl ethers in hexane were performed in the presence of s-butyllithium and (-)-α-isosparteine which is a C2-symmetric chiral ligand for the alkyllithium reagent. The reactions of (Z)-or (E)-allyl 3-trimethylsilylpropargyl ethers at -78℃ showed good diastereoselectivities (74-100%) and moderate enantioselectivities (29-71%). The absolute configurations of the rearrangement products were determined by the corresponding Mosher's esters. It was found that (-)-α -isosparteine induced (R) configuration at the hydroxy carbon and syn stereochemistry more favorably. The possible transition state is discussed.
Page
732 - 739
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