Synlett 2014; 25(14): 2085-2086
DOI: 10.1055/s-0034-1378382
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© Georg Thieme Verlag Stuttgart · New York

Applications of Allenylsilanes in Organic Synthesis

Sharada Prasanna Swain
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan    Email: d9623889@oz.nthu.edu.tw
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Publication History

Publication Date:
28 July 2014 (online)

Introduction

Allenylsilanes 2 are versatile reagents widely used in organic synthesis.[1] Generally, allenylsilanes react as propargyl anion equivalents in Lewis acid mediated[2] or thermal[3] nucleophilic addition to electrophiles such as carbonyls, imines, Selectfluor, and N-bromosuccinimide, etc.[1] [4] [5] The regiospecific addition of allenylsilanes provides a β-vinyl cation, which is stabilized by a C–Si bond, which is called β effect. The C–Si bond in allenylsilanes is oriented cis-coplanar to the p-orbital of the carbocation and provides direct stabilization.[5] Allenylsilanes undergo [3+2] annulations with α,β-unsaturated carbonyls, carbonyl compounds, imines, and nitrosyl cations to form cyclo-pentenones, dihydrofurans, dihydropyrroles, and isoxazoles, respectively.[1] [4] [5]

The efficient methods for the synthesis of allenylsilanes 2 are copper-mediated 1,3-substitution reactions of carbon nucleophiles to propargylic substrates 1 having a leaving group at the propargylic position.[6] [7]

Zoom Image
Scheme 1 Synthesis of allenylsilanes
 
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