Rapid Selective Defunctionalization of the Carbonyl Group of α,β-Unsaturated Ketones with Trialkoxylsilane/ZnX₂

Abstract

Reduction of the carbonyl group of ketones to a methylene unit is widely applied in organic syntheses. In this article, we report that trialkoxylsilane/Zn-based catalyst systems may be applied in the reduction of the carbonyl groups of α,β-unsaturated ketones to methylene units under very mild conditions. In comparison with other Zn-based catalysts, excellent rates and high conversions of α,β-unsaturated ketones to methylene units are obtained using trialkoxylsilane/ZnI₂ or ZnCl₂. And the same time, the hydrosilylation reaction product could only be detected when using CuI, CuCl, or FeCl₃. No reaction could be conducted by using trialkoxylsilane/CoCl₂ or NiCl₂, in comparison with Zn-based catalysts.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT

Keywords:

• Defunctionalization of carbonyl group
• trialkoxylsilane/ZnX₂
• α,β-unsaturated ketone

Acknowledgments

We are grateful to the Fund of Zhejiang province (2008C14041) and Technologies R&D Program of Hangzhou city (20100331T16) for financial support.