15673-05-9Relevant articles and documents
Pd-Catalyzed intermolecular C-H bond arylation reactions: Effect of bulkiness of carboxylate ligands
Tanji, Yutaka,Hamaguchi, Ryo,Tsuji, Yasushi,Fujihara, Tetsuaki
supporting information, p. 3843 - 3846 (2020/04/15)
A bulky carboxylic acid bearing one 1-adamantylmethyl and two methyl substituents at the α-position is demonstrated to work as an efficient carboxylate ligand source in Pd-catalyzed intermolecular C(sp2)-H bond arylation reactions. The reactions proceeded smoothly under mild conditions, taking advantage of the steric bulk of the carboxylate ligands.
Efficient nickel-catalyzed hydrocyanation of alkenes using acetone cyanohydrin as a safer cyano source
Nemoto, Koji,Nagafuchi, Tsuyoshi,Tominaga, Ken-ichi,Sato, Kazuhiko
, p. 3199 - 3203 (2016/07/06)
An active nickel catalyst prepared in situ from a Ni(II) compound, phosphine ligand, and zinc powder was found to be an efficient catalyst system for the hydrocyanation of various alkenes using acetone cyanohydrin as a safer cyano source. The combination of NiCl2·6H2O and 1,3-bis(diphenylphosphino)propane was the most efficient catalyst precursor in DMF. Under the optimized conditions, various styrenes, heterocyclic alkenes, and aliphatic alkenes were converted to their corresponding nitriles in excellent yields.
Electron-Transfer-Photosensitized Conjugate Alkylation
Fagnoni, Maurizio,Mella, Mariella,Albini, Angelo
, p. 4026 - 4033 (2007/10/03)
Photoinduced electron transfer (PET) from an aliphatic donor to a sensitizer and fragmentation of the radical cation leads to alkyl radicals. Radical alkylation of electron-withdrawing substituted alkenes and alkynes has been obtained in this way, and its scope has been explored. Effective sensitizers are tetramethyl pyromellitate (TMPM), 1,4-dicyanonaphthalene (in combination with biphenyl, DCN/BP), and 1,2,4,5-tetracyanobenzene. Radical precursors are tetraalkylstannanes, 2,2-dialkyldioxolanes, and, less efficiently, carboxylic acids. Steady-state and flash photolysis experiments show that escape out of cage of radical ions is the main factor determining the yield of radical formation. This is efficient with triplet sensitizers such as TMPM, while with singlet sensitizers, the use of a "cosensitizer" is required, as in the DCN/BP system. Radical cations containing primary alkyl radicals escape and fragment more efficiently than those containing tertiary radicals. The thus-formed radicals are trapped by electron-withdrawing substituted alkenes, and the relative efficiency is determined by the rate of radical addition, in accord with the proposed mechanism. Among the alkynes tested, only dimethyl acetylenedicarboxylate reacts, and the order of radical reactivity is different. It is suggested that a different mechanism operates in this case and involves assistance by the alkyne to the radical cation fragmentation.
