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Updated: Jun 13, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Lewis acid catalyzed cycloaddition of methylenecyclopropanes with salicylaldehydes
1State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Abstract:
Lewis acid catalyzed cycloaddition of methylenecyclopropanes (MCPs) with o-quinonemethide analogues, derived from the corresponding salicylaldehydes and CH(OEt)(3), produces the corresponding cycloadducts 3 in moderate to high yields at room temperature (20 degrees C). Moreover, the compounds 3 can be transformed to the indene derivatives 5 at high temperature. Plausible mechanisms have been proposed on the basis of control experiments.
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Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.

