Manganese-Catalyzed Ring Opening of Benzofurans and Its Application to Insertion of Heteroatoms into the C2-O Bond.

An intramolecular hydroarylation of aryl alkynylphosphonates (I) and (III) promoted by a gold/silver catalyst affords phosphacoumarins (II) and (IV), resp., in moderate to good yields via a 6-endo-dig cyclization.

Gold‐Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins

Coumarins are an important class of natural heterocyclic compounds that have attracted considerable synthetic and pharmacological interest due to their various biological activities. This review emphasizes on the synthetic methods for the preparation of dialkyl 2-oxo-2H-1-benzo- pyran-3-phosphonates and alkyl 1,2-benzoxaphosphorin-3-carboxylates. Their chemical properties as acceptors in conjugate addition reactions, [2+2] and [3+2] cycloaddition reactions are discussed.

Synthesis and Chemical Properties of 3-Phosphono-coumarins and 1,2-Benzoxaphosphorins as Precursors for Bioactive Compounds

A convenient synthesis of 8,8’-spirobi(chromano-1,2-oxaphosphinine) derivatives

Bis(benzo[e]-1,2-oxaphosphinin-2-oxid-4(7)-yl)butane (-benzene) derivatives were synthesized for the first time both on the basis of reactions of diacetylene with P,P, P-trihalobenzo-1,3,2-dioxaphopholes and on the basis of reactions of bis(P,P,P-trihalobenzo-1,3,2-dioxaphosphol-5-yl)bytane (-benzene) with phenylacetylene.

P,P,P-Trihalobenzo-1,3,2-Dioxaphopholes in the Reaction with Aliphatic Acetylenes and Diacetylenes: Synthesis of New Phosphacoumarins

The account covers a new reaction in phosphorus chemistry, namely, the interaction of 2,2,2-trihalobenzo-1,3,2-dioxaphospholes with aryl(alkyl)acetylenes, which leads to the formation of benzo[e]-1,2-oxaphosphinine derivatives, or “phosphacoumarins.” The easy formation of a P-C bond and phosphoryl group, the ipso-substitution of the oxygen atom by the carbon one, and selective chlorination para to endocyclic oxygen are realized under mild conditions in this reaction. The ipso-substitution of a tertiary butyl group and a bromine atom also takes place in some cases.

Reaction of P,P,P-trihalogenbenzo-1,3,2-dioxaphospholes with terminal acetylenes: Phosphorus-carbon bond formation and the ipso-substitution of oxygen by carbon

A. V. Nemtarev

Papers

Reaction of P,P,P-trihalogenbenzo-1,3,2-dioxaphospholes with terminal acetylenes: Phosphorus-carbon bond formation and the ipso-substitution of oxygen by carbon