Zinc(II) Iodide-Triethylsilane: A Novel Mild Reduction System for Direct Deoxygenation of Aryl Aldehydes, Ketones, and α,β-Unsaturated Enones

Abstract

ZnI₂-TESH has been found to be a novel mild and efficient reduction system. This reagent, in contrast to the traditional ionic deoxygenation systems (TFA-R₃SiH, BF₃˙OEt₂-R₃SiH, etc.), could directly deoxygenate different kinds of carbonyl compounds such as aryl aldehydes, ketones, and α,β-unsaturated enones to the corresponding hydrocarbons in moderate to excellent yields.

zinc iodide - ionic hydrogenation - deoxygenation - carbonyl compounds - hydrocarbons

References and Notes

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General Procedure for the Synthesis of Product 2: To a stirred solution of substrate 1 (1 mmol) in 1,2-dichloroethane (5 mL) at r.t. was added solid zinc iodide (638 mg, 2 mmol).Then, triethylsilane (1.9 mL, 10 mmol) was added slowly to the above suspension via a syringe. The reaction mixture was stirred at r.t. until 1 was completely disappeared or there was no further conversion (TLC inspection). The stirring was stopped, and then the reaction mixture was filtered through Celite. The Celite was washed with CH₂Cl₂ (4 × 15 mL). The combined filtrate was washed with H₂O and sat. brine, and then dried over anhyd Na₂SO₄. After concentration, the residue was chromatographed on silica gel, eluting with 0-25% EtOAc in cyclohexane.

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