A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

• Kay M. Brummond and
• Joshua M. Osbourn

Beilstein J. Org. Chem. 2010, 6, No. 33, doi:10.3762/bjoc.6.33

• rearrangement of the propargyl acetate 9a using transition metal catalysis (AuCl3 10 mol %, toluene, 1 h, rt) led to hydrolysis of the allenyl acetate functionality. This densely functionalized alkylidene cyclobutene 10a is postulated to arise via the [2 + 2] cycloaddition reaction between the alkyne and the

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• (Scheme 9). As shown in Scheme 9, the strategy employed allows the selective formation or 1- or 3-substituted derivatives, where the coupling of a C2 acetylenic synthon and a C2 epoxide synthon provides a new and useful [2+2] annulation strategy for the preparation of the strained cyclobutene ring. The

• . Intramolecular cyclization of TMS-epoxyallylsilanes. Spiro-cyclopropanation from oxoallylsilanes. Cyclobutane formation from hydroxy-functionalized allysilanes. Cyclobutene formation from vinyltin cuprates and epoxides. Silylcupration of 1,2-propadiene and reaction with α,β-unsaturated nitriles. Cycloheptane