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Synlett 2005(10): 1555-1558  
DOI: 10.1055/s-2005-869853
LETTER
© Georg Thieme Verlag Stuttgart · New York

Enantioselective Hydroxyvinylation with Lithioethenes

Yi Yuan, Anne Harrison-Marchand, Jacques Maddaluno*
Laboratoire des Fonctions Azotées & Oxygénées Complexes de l’IRCOF, UMR 6014 CNRS, Université de Rouen, 76821 Mont Saint-Aignan Cedex, France
Fax: +33(2)35522971; e-Mail: jmaddalu@crihan.fr;
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Publication History

Received 26 April 2005
Publication Date:
07 June 2005 (online)

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Abstract

The enantioselective addition of lithioethenes to aldehydes was studied. Such asymmetric approach of the hydroxyvinylation is reported for the first time with promising ee, (up to 70% at -78 °C in THF), using mixed aggregates of the vinyllithium species and a chiral lithium amide.

Key words

mixed aggregates vinyllithiums - chiral lithium amide - asymmetric vinylation

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The following may be considered as general procedure for the enantioselective hydroxyvinylation of aldehyde: in a flask A, a 1.7 M solution of t-BuLi in pentane (0.5 mL, 0.85 mmol, 2.1 equiv/1c) was added at -78 °C to a solution of 2-bromovinyltrimethylsilane 1c (90% trans: 78.8 mg, 0.4 mmol, 1 equiv/5) in THF (2 mL) and the resulting mixture was stirred at -78 °C for 1 h then 30 min at -20 °C. In a flask B, a 1.7 M solution of t-BuLi in pentane (0.35 mL, 0.6 mmol, 1 equiv/amine) was added at -78 °C to a solution of (S)-1-benzyl-3-diphenylmethylaminopyrrolidine (205 mg, 0.6 mmol, 1.5 equiv/2c or 5) in THF (1.5 mL) and the resulting mixture was stirred at the same temperature for 1 h. The solution in flask A containing 2c was transferred to flask B and stirred at T °C (see Table [1] ) for 1 h. A solution of aldehyde (0.4 mmol) in THF (1 mL) was added over a period of 20 min (maintaining the temperature at -78 °C) to the mixed aggregate freshly prepared above and the reaction mixture was stirred at -78 °C for 10 h. After addition of brine (10 mL), the organic layer was extracted with Et2O (3 × 15 mL), dried (MgSO4), filtered and concentrated. The residue was purified by flash chromatography on silica gel (heptane-EtOAc, 5: 1).

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Duguet, N.; Paté, F.; Harrison-Marchand, A.; Maddaluno, J.; Oulyadi, H. to be published.