Direct Formation of Reactive Alkynyltrichlorotins from 1-Alkynes, SnCl<sub>4</sub>, and Bu<sub>3</sub>N. A Mild Alkynylation Reagent of Aldehydes, Acetals, and Enones
A reagent system of 1-alkyne, SnCl4, and Bu3N alkynylates aldehydes, acetals, and enones under mild reaction conditions giving acetylenic alcohols, acetylenic ethers, and acetylenic ketones, respectively, in high yields. Alkynyltrichlorotins are shown to be the reactive species for these reactions.
A Convenient Method for the Preparation of Secondary Propargylic Ethers. The Reaction of Acetals with 1-Trimethylsilylalkynes Promoted by the Combined Use of Catalytic Amounts of Tin(IV) Chloride and Zinc Chloride
In the coexistence of catalytic amounts of SnCl4 and ZnCl2, acetals undergo a coupling with 1-trimethylsilylalkynes in good yields to give secondary propargylic ethers, which are also directly produced from aldehydes by the reaction with alkoxytrimethylsilanes and 1-trimethylsilylalkynes under the same conditions.
Pd(0) mediates the cross-coupling of organotins with a variety of alpha-haloethers/thioethers in moderate-good yields whereas an alpha-chloroacetoxyalkane failed to react. Tandem cyclization-coupling of the alkyl-palladium intermediate affords novel access to heterocycles.