Synthesis of Odd-membered Rings by the Reaction of β-Carbonylallylsilane or its Derivative as a Carbon 1,3-Dipole

Syntheses and reactions of β-carbonylallylsilane, conjugated allylsilane with a carbonyl group at the β-position, or its equivalent are reviewed. The method of the preparation of this moiety can be classified into (1) the introduction of silyl group at the allylic position of α,β-unsaturated carbonyl compounds, (2) carbonylation of allylsilane at the β-position, (3) elimination from pre-constructed β- silyl carbonyl compounds, (4) The Horner-Wadsworth-Emmons coupling reaction, and (5) others. β-Carbonylallylsilane can formally react with both an electrophile and a nucleophile at the same carbon, which makes it easy to synthesize odd membered cyclic compounds, such as five or seven-membered carbocycles related to terpenoids. The reaction of this unit with C=O or C=C produces γ-lactone or cyclopentane, respectively. The Nazarov cyclization of α-(trimethylsilylmethyl)divinyl ketones and the self-cyclization of 2-(trimethylsilylmethyl)pentadienal also provide new entries to five-membered carbocycle. The homo-Diels- Alder reaction and the homo-Cope rearrangement are developed using β-(hydroxymethyl)allylsilane derivatives as the carbon 1,3-dipole.