Related Experiment Video
Updated: Oct 3, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Homolytic carbostannylation of alkenes and alkynes with tributylstannyl enolates
1Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
Abstract:
In the presence of AIBN, tributylstannyl enolates derived from aromatic ketones reacted with electron-deficient alkenes and a variety of alkynes to give the corresponding carbostannylated adducts. The reactions with methyl acrylate gave alpha-tributylstannylmethyl-gamma-ketoesters, unlike the known Michael-type reaction of stannyl enolates forming delta-ketoesters. The carbostannylation of alkynes proceeded in an anti addition mode to afford beta,gamma-unsaturated ketones. The reactivity of stannyl enolates as radical transfer agents could be utilized for radical cyclization of 1,6-enynes.
More Related Videos
Related Concept Videos
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
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.
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Hydroboration-Oxidation of Alkenes
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.

