10.1021/acs.orglett.5b01630
The research describes a Pd-catalyzed regiodivergent hydroesterification of aryl olefins with phenyl formate, which allows for the selective synthesis of either linear or branched phenyl arylpropanoates in good yields and high regioselectivities without the use of toxic CO gas. The study found that the choice of ligand significantly influences the reaction efficiency and selectivity, with bidentate ligands like dppe, dppp, dppb, and dppf favoring linear esters, while monodentate ligands like PPh3 favored branched esters. Key chemicals used in the process include aryl olefins, phenyl formate (HCOOPh), Pd(OAc)2 as the catalyst, various phosphine ligands, and additives such as HCOOH or CH3COOH. The researchers propose a plausible catalytic cycle involving the oxidative addition of Pd(0) to HCOOPh, followed by hydropalladation of the olefin substrate, migratory insertion, and reduction elimination to form the esters. The reaction mechanism is not fully understood and requires further study, but the findings suggest that the regioselectivity is likely determined in the migratory insertion step. The developed method is operationally simple, avoids the handling of toxic gases, and has potential applications in organic synthesis.
10.1055/s-1988-27683
Yoshibiko Ito et al. describe the preparation of o-di(formamido)arenes through formylation of o-diaminoarenes using phenyl formate, which yielded better results than other formylating agents. The key step involves the dehydration of o-di(formamido)arenes with trichloromethyl chloroformate at low temperatures (-78°C to 0°C) in the presence of triethylamine, resulting in significantly higher yields compared to previous methods. The study reports the synthesis of several new o-disocyanoarenes with yields ranging from 51% to 92%, as detailed in a table that includes product yields, melting points, molecular formulas, IR spectra, and 'H-NMR data. The authors also note that the reaction temperature is crucial for achieving high yields. The synthesized compounds are being investigated for potential applications in polymerization processes.
