Synthesis of malonic esters by the catalytic addition of methyl formate to α,β-unsaturated esters

An effective approach to aryl-substituted propanoic acids via the Pd-catalyzed hydrocarboxylation of stilbenes

An effective Pd(0)-catalyzed hydrocarboxylation of substituted stilbenes with formic acid and HCOOPh is described. A variety of aryl-substituted propanoic acids are obtained in good yields without using external toxic CO gas.

Pd-Catalyzed Regiodivergent Hydroesterification of Aryl Olefins with Phenyl Formate

An effective Pd-catalyzed regiodivergent hydroesterification of aryl olefins with phenyl formate is described. Either linear or branched phenyl arylpropanoates can be obtained in good yields with high regioselectivities by the judicious choice of ligand without the use of toxic CO gas.

A palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate. A facile approach to optically active dihydrocoumarins

An effective palladium-catalyzed enantioselective hydroesterification of alkenylphenols with phenyl formate as a CO source is described.

A palladium-catalyzed regioselective hydroesterification of alkenylphenols to lactones with phenyl formate as CO source

An effective Pd(OAc)2-PPh3 catalyzed hydroesterification of alkenylphenols with phenyl formate as CO surrogate is described. A variety of lactones are obtained in generally high yields with high regioselectivities. In one case, 76% ee is obtained with a chiral ligand.

Photoaddition reactions of 1,2-diketones with silyl ketene acetals. formation of beta-hydroxy-gamma-ketoesters

Photochemical reactions taking place between 1,2-diketones and silyl ketene acetals and their excited state reaction mechanisms have been explored. Irradiation of benzene, acetone, or acetonitrile solutions containing 1,2-diketones and silyl ketene acetals is observed to promote formation of 1,4-dioxenes, resulting from [4 + 2]-cycloaddition, oxetanes, arising by Paterno-Buchi processes, and beta-hydroxy-gamma-ketoesters, generated by SET-promoted Claisen-type condensation. These competitive pathways leading from the excited states of the 1,2-diketones to these products are influenced by solvent polarity and the nature of the silyl ketene acetal and 1,2-diketone. The Claisen-type condensation process, following an SET desilylation pathway and predominating when the photoreactions are carried out in the polar solvent acetonitrile, represents an efficient method to prepare a variety of diversely substituted beta-hydoxy-gamma-ketoesters.

Hydroamidation of Alkenes with N-Substituted Formamides

Hydroamidation of olefins with N-substituted formamides is performed with dodecacarbonyltriruthenium (Ru3(CO)12) at 180°C under N2 or CO atmosphere in toluene and in a series of ionic liquids. Yields of 99% with 94–97% exo selectivity are found in the addition of N-methylformamide to 2-norbornene under CO both in toluene and in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][NTf2]. The presence of CO or a phosphine is necessary for significant reaction to occur, with CO more effective than triphenylphosphine in all ionic liquids investigated. Reasonable yields are achieved at low pressures, in contrast to most reported hydroamidations. Conversion, exo-selectivity, and selectivity fall with increasing steric bulk of the N-formamide substituent, and disubstituted formamides are inactive. Of the terminal alkenes investigated, only styrene can be hydroamidated.

Evolution of carbonylation catalysis: no need for carbon monoxide

Progress in organometallic catalysis began with the discovery of the Roelen reaction (hydroformylation with carbon monoxide and hydrogen) in 1938 and the Reppe reaction (hydrocarboxylation with carbon monoxide and water) in 1939. Since then, carbonylation chemistry by using carbon monoxide has occupied a central position in organometallic chemistry, as it relates to organic synthesis. There is, however, the problem of using gaseous carbon monoxide (a toxic greenhouse gas) in this chemistry. Recently, some strategies that address this issue have appeared. This minireview describes carbonylation reactions that can be conducted without the direct use of carbon monoxide. These carbonylation reactions provide reliable and accessible tools for synthetic organic chemists.