Regioselective Rhodium-Catalyzed Addition of Arylboronic Acids to Alkynes with a Pyridine-Substituted Water-Soluble Ligand

Alkynyl heteroaromatic compounds reacted with arylboronic acids to give addition products in the presence of [Rh(COD)Cl]2 and pyridine-substituted water-soluble ligand. The reactions proceed to give trisubstituted alkenes with high regioselectivity

Rhodium-Catalyzed Addition of Arylboronic Acids to Alkynyl Aza-Heteroaromatic Compounds in Water

Alkynyl heteroaromatic compounds reacted with arylboronic acids to give addition products in the presence of a rhodium catalyst. The best results were obtained when a novel pyridine-substituted water-soluble phosphine ligand was used. The reactions proceed to give trisubstituted alkenes from various arylboronic acids and alkynyl heteroaromatic compounds with high regioselectivity. Only alkynes with a nitrogen atom in proximity to the triple bond were converted to the corresponding alkenes, as expected for a chelation-controlled addition

Rhodium-Catalyzed Addition of Arylboronic Acids to Alkynyl Aza-Heteroaromatic Compounds in Water

Alkynyl heteroaromatic compounds reacted with arylboronic acids to give addition products in the presence of a rhodium catalyst. The best results were obtained when a novel pyridine-substituted water-soluble phosphine ligand was used. The reactions proceed to give trisubstituted alkenes from various arylboronic acids and alkynyl heteroaromatic compounds with high regioselectivity. Only alkynes with a nitrogen atom in proximity to the triple bond were converted to the corresponding alkenes, as expected for a chelation-controlled addition

Synthesis of 5-Vinylideneoxazolidin-2-ones by DBU-Mediated CO₂-Fixation Reaction of 4-(Benzylamino)-2-butynyl Carbonates and Benzoates

A CO2-fixation reaction of 4-(benzylamino)-2-butynyl carbonates and benzoates, carried out in the presence of DBU, provides substituted 5-vinylideneoxazolidin-2-ones. The reaction has been successfully applied to the CO2-recycling process and fixation of atmospheric CO2

Palladium-Catalyzed Carbon Dioxide Elimination−Fixation Reaction of 4-Methoxycarbonyloxy-2-buten-1-ols

A new type of palladium-catalyzed CO2 recycling reaction using allylic carbonates is described. Reaction of trans-4-methoxycarbonyloxy-2-buten-1-ols in the presence of a palladium catalyst produces cyclic carbonates having a vinyl group via a CO2 elimination−fixation process. A variety of allylic carbonates participate in the reaction giving cyclic carbonates with high efficiencies. Stereoselective construction of trans-cyclic carbonates is achieved by using nonsymmetric substrates. An enantiospecific reaction proceeds to give chiral cyclic carbonate when a chiral methyl-substituted substrate is subjected to the reaction conditions

Diastereoselective Construction of 7-Methylenebicyclo[3.2.1]oct-3-en-2-one Derivatives by Palladium-Catalyzed Cyclization of Propargylic Acetates with 2-Oxocyclohex-3-enecarboxylates

The reaction of propargylic acetates with 2-oxocyclohex-3-enecarboxylates in the presence of a palladium catalyst is described. Substituted 7-methylenebicyclo[3.2.1]oct-3-en-2-ones were synthesized in a highly diastereoselective manner

Palladium-Catalyzed Enantiospecific Reaction of Propargylic Carbonates with Phenols: Cascade Chirality Transfer

A cascade chirality transfer process has been achieved by the palladium-catalyzed reaction of substituted propargylic carbonates with phenols. The reaction proceeds in a highly enantiospecific manner to produce chiral cyclic carbonates, which supports the existence of the π-propargylpalladium intermediate in the reaction mechanism. The (E)- and (Z)-selectivity of the products can be controlled by choice of the phosphine ligand

Stereoselective Construction of Substituted Chromans by Palladium-Catalyzed Cyclization of Propargylic Carbonates with 2-(2-Hydroxyphenyl)acetates

Highly substituted chromans have been constructed in a highly stereoselective manner by a palladium-catalyzed reaction of propargylic carbonates with 2-(2-hydroxyphenyl)acetates. Enantioselective reactions also successfully proceeded to give the optically active chromans with high enantioselectivity

Stereoselective Construction of Substituted Chromans by Palladium-Catalyzed Cyclization of Propargylic Carbonates with 2-(2-Hydroxyphenyl)acetates

Highly substituted chromans have been constructed in a highly stereoselective manner by a palladium-catalyzed reaction of propargylic carbonates with 2-(2-hydroxyphenyl)acetates. Enantioselective reactions also successfully proceeded to give the optically active chromans with high enantioselectivity

Palladium-Catalyzed Ring Expansion Reaction of (<i>Z</i>)-1-(1,3-Butadienyl)cyclobutanols with Aryl Iodides. Stereospecific Synthesis of (<i>Z</i>)-2-(3-Aryl-1-propenyl)cyclopentanones

A novel type of cascade ring expansion process has been developed by the palladium-catalyzed reaction of (Z)-1-(1,3-butadienyl)cyclobutanols with aryl iodides. The reaction proceeds in a stereospecific manner to produce (Z)-2-(3-aryl-1-propenyl)cyclopentanones. It has also been found that regioselective α-arylation of alkenyl cyclopentanones proceeds to afford the α-arylated cyclopentanones