High-Yielding and Rapid Carbon–Carbon Bond Formation from Alcohols: Allylation by Means of TiCl₄

Abstract

TiCl₄ efficiently promotes high yield (80–99%) replacement of OH in tertiary, benzylic, and allylic alcohols, and even nonactivated secondary alcohols, by an allyl group. The reaction usually proceeds within minutes at room temperature.

Key words

alcohols - C–C bonds - allylation - allyltrimethylsilane - Lewis acid - TiCl₄

• References and Notes

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• 17 Typical Experimental Procedure To a stirred solution of alcohol 4 (1 mmol) in CH₂Cl₂ (2 mL) at r.t. was added TiCl₄ (0.8 mmol, 1 M in CH₂Cl₂) and allyltrimethylsilane 2 (1.2 mmol). The mixture was stirred for the indicated time (see Table 2). After completion of the reaction was indicated by TLC, excess of solvent was evaporated, and the product was flash chromatographed using EtOAc–hexane as eluents (1:99) to afford pure allylated product 5. NMR spectra were identical to those reported