1,2-Diacylation of Alkynes Using Acyl Fluorides and Acylsilanes by P(III)/P(V) Catalysis.

We report herein the phosphine-catalyzed 1,2-diacylation of alkynes using acyl fluorides and acylsilanes as acyl sources. The key to the success of the reaction is a formal oxidative addition-ligand metathesis-reductive elimination cycle based on phosphine redox catalysis, which allows for the installation of two different acyl groups into an alkyne in a regioselective manner.

Three-Component Coupling of Acyl Fluorides, Silyl Enol Ethers, and Alkynes by P(III)/P(V) Catalysis.

We report herein on the phosphine-catalyzed hydrovinylation reaction by three-component coupling of acyl fluorides, silyl enol ethers, and alkynoates. The key to the success of the reaction is the formal transmetalation between pentacoordinate P(V) species (i.e., fluorophosphorane) and a silyl enol ether, which allows for C-C bond formation between the polarity-mismatched sites. The bond formation that cannot be attained even by transition metal catalysis is accomplished by a P(III)/P(V) manifold.

Aryne-Induced SNAr/Dearylation Strategy for the Synthesis of Fluorinated Dibenzophospholes from Triarylphosphines via a P(V) Intermediate.

We report on a method for the synthesis of fluorinated dibenzophospholes using triarylphosphine via dearylative annulation with an aryne. This intermolecular annulation allows the preparation of a variety of fluorinated dibenzophospholes from simple building blocks. The key to the success of this dearylative annulation is the formation of a five-coordinated tetraarylfluorophosphorane. In this work, we successfully synthesized stable tetraarylfluorophosphorane, the structure of which was unambiguously determined by X-ray crystallography.

Cyclization of Bisphosphines to Phosphacycles via the Cleavage of Two Carbon-Phosphorus Bonds by Nickel Catalysis.

The nickel-catalyzed cyclization of bisphosphine derivatives to form various phosphacycles is reported. The reaction proceeds via the cleavage of two carbon-phosphorus bonds of the bisphosphine. Unlike the previously reported palladium catalysts, the use of nickel as a catalyst allows for the cyclization that requires C(alkyl)-P bond cleavage. A phospha-nickelacycle intermediate was successfully isolated and characterized by X-ray crystallography.