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Synlett 2008(7): 999-1004  
DOI: 10.1055/s-2008-1072513
LETTER
© Georg Thieme Verlag Stuttgart · New York

Julia Olefination as a General Route to Phenyl (α-Fluoro)vinyl Sulfones

Maggie He, Arun K. Ghosh, Barbara Zajc*
Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, NY 10031, USA
Fax: +1(212)6506107; e-Mail: barbaraz@sci.ccny.cuny.edu;
Further Information

Publication History

Received 2 September 2007
Publication Date:
28 March 2008 (online)

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Abstract

Mild and efficient synthesis of phenyl (α-fluoro)vinyl sulfones via condensation of aldehydes and a ketone with a novel benzothiazolyl based bis-sulfone reagent is reported and this proceeds with moderate to good Z-stereoselectivity.

Key words

fluorination - olefination - Julia - fluorovinyl sulfones - benzothiazole

1

Undergraduate research participant.

21

In a typical experiment, to a mixture of aldehyde (1 mol equiv), bis-sulfone 3 (1.3 mol equiv) and anhyd MgBr2 (1.8 mol equiv) in anhyd THF (5 mL per mmol of aldehyde), a solution of DBU (3.9 mol equiv) in anhyd THF (5 mL per mmol of aldehyde) was added. The mixture was stirred at r.t., until the disappearance of the aldehyde was observed by TLC. Aqueous NH4Cl was added and the mixture was extracted with EtOAc (3×). The organic layer was washed with H2O and brine, dried over anhyd Na2SO4 and the solvent was evaporated.

23

Conditions as reported in ref. 12b were used (N-benzylpiperidone: 1.2 mol equiv; 3: 1 mol equiv; DBU: 1.4 mol equiv; THF: 5 mL per mmol of 3; r.t., 6 h).