A palladium-isocyanide complex opens the two four-membered rings of benzocyclobutenone and silacyclobutane to merge them into an eight-membered ring skeleton. The present reaction provides a unique example of an intermolecular cross metathesis-type reaction between covalent σ-bonds of low polarity.

Cyclobutanols and cyclopropanols underwent ring-opening fluorination upon treatment with Selectfluor in the presence of a substoichiometric amount of a silver salt. The reaction provides an efficient method to synthesize γ-and β-fluoroalkyl ketones.Organofluorine compounds have attracted significant attention in pharmaceuticals, agrochemicals, and materials science. The strong demand for organofluorine compounds has spurred the development of new synthetic means for organofluorine compounds.2,3 Herein we report a ring-opening fluorination reaction of cyclobutanols and cyclopropanols catalyzed by silver. A fluorine atom is introduced in a site-selective manner to afford the γ-and β-fluoroalkyl ketones.Cyclobutanols are facilely prepared by well-established methods such as [2+2] cycloaddition of alkenes with ketenes followed by an addition reaction of Grignard reagents.4 They undergo ring-opening reactions upon treatment with transitionmetal catalysts.5 Oxidation of cyclobutanols also induces ring opening.6 As a continuation of our previous studies on the ringopening reactions of cyclobutanol derivatives, 7 we examined a reaction with fluorinating agents to find that cyclobutanol 1a underwent a ring-opening fluorination reaction when treated with Selectfluor (4 equiv) 8 in the presence of Ag I F (20 mol %) in a benzene/water biphasic solvent at 60°C for 5 h (Scheme 1).

A convenient method for the synthesis of 1,3-dienes from readily available compounds is reported. 2-Aryoxy-1,3-dienes are produced stereoselectively by a nickel-catalyzed reaction of propargyl carbonates with phenols. Functional group tolerance is broad to allow iodo, formyl, and boryl groups. The resulting 1,3-dienes are of much synthetic value because they can participate in a wide variety of reactions, including the Diels–Alder reaction.