Synlett 2004(7): 1288-1290  
DOI: 10.1055/s-2004-822918
LETTER
© Georg Thieme Verlag Stuttgart · New York

Stereoselective Preparation of Deuteriated Dienes by Ring Fragmentation of Metallated Cyclopropylcarbinols

Elinor Zohar, Mirit Ram, Ilan Marek*
Department of Chemistry and Institute of Catalysis Science and Technology, Technion-Israel Institute of Technology, Technion City, 32000 Haifa, Israel
Fax: +972(4)8293709; e-Mail: chilanm@tx.technion.ac.il;
Further Information

Publication History

Received 15 February 2004
Publication Date:
28 April 2004 (online)

Abstract

The hydroalumination reaction of cyclopropenylcarbinols initially leads to the alumino-cyclopropylcarbinol derivatives, which is followed by an elimination reaction to give the corresponding substituted dienes as unique isomers and in good yields. The use of LiAlD4 as reducing agent provides stereoselectively substituted deuteriodienes.

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General Procedure for the Preparation of Dienes from Cyclopropenylcarbinols 1a-g: LiAlH4 (or LiAlD4, 1 M solution in Et2O, 1 mmol) was added to a stirred solution of 1a-g (1 mmol) in 5 mL of benzene at 5 °C. The reaction mixture was then heated to 80 °C for several hours and the sequential reduction and elimination reactions were followed by TLC. When the transformation was complete, 1 M aq solution of HCl (3 mL) was added and the aqueous layer was extracted with Et2O (3 × 5 mL). The combined organic phases were dried over MgSO4, filtered and the solvent was removed under reduced pressure. Chromatography on silica gel (eluent: hexane) gave the dienes 4a-k in yields indicated in Table [1] .