The author of 《Cationic Co(I)-Intermediates for Hydrofunctionalization Reactions: Regio- and Enantioselective Cobalt-Catalyzed 1,2-Hydroboration of 1,3-Dienes》 were Duvvuri, Krishnaja; Dewese, Kendra R.; Parsutkar, Mahesh M.; Jing, Stanley M.; Mehta, Milauni M.; Gallucci, Judith C.; RajanBabu, T. V.. And the article was published in Journal of the American Chemical Society in 2019. Product Details of 1779-49-3 The author mentioned the following in the article:
Much of the recent work on catalytic hydroboration of alkenes has focused on simple alkenes and styrene derivatives with few examples of reactions of 1,3-dienes, which are reported to undergo mostly 1,4-additions to give allylic boronates. Reduced Co catalysts generated from 1,n-bis-diphenylphosphinoalkane complexes [Ph2P-(CH2)n-PPh2]CoX2; (n = 1-5) or from (2-oxazolinyl)phenyldiarylphosphine complexes [(G-PHOX)CoX2] (G = 4-substituent on oxazoline ring) effect selective 1,2-, 1,4-, or 4,3-additions of pinacolborane (HBPin) to a variety of 1,3-dienes depending on the ligands chosen. Conditions optimize the 1,2-additions The reactive catalysts can be generated from the Co(II)-complexes using trimethylaluminum, Me aluminoxane, or activated Zn in the presence of Na tetrakis[(3,5-trifluoromethyl)phenyl]borate (NaBARF). The complex, (dppp)CoCl2, gives the best results (ratio of 1,2- to 1,4-addition >95:5) for a variety of linear terminal 1,3-dienes and 2-substituted 1,3-dienes. The [(PHOX)CoX2] (X = Cl, Br) complexes give mostly 1,4-addition with linear unsubstituted 1,3-dienes, but, surprisingly, selective 1,2-additions with 2-substituted or 2,3-disubstituted 1,3-dienes. Isolated and fully characterized (x-ray crystallog.) Co(I)-complexes, (dppp)3Co2Cl2 and [(S,S)-BDPP]3Co2Cl2, do not catalyze the reaction unless activated by a Lewis acid or NaBARF, suggesting a key role for a cationic Co(I) species in the catalytic cycle. Regio- and enantioselective 1,2-hydroborations of 2-substituted 1,3-dienes are best accomplished using a catalyst prepared via activation of a chiral phosphinooxazoline-Co(II) complex with Zn and NaBARF. A number of common functional groups, among them, -OBn, -OTBS, -OTs, N-phthalimido- groups, are tolerated, and er’s > 95:5 were obtained for several dienes including 1-alkenylcycloalk-1-enes. This operationally simple reaction expands the realm of asym. hydroboration to provide direct access to a number of nearly enantiopure homoallylic boronates, which are not readily accessible by current methods. The resulting boronates were converted into the corresponding alcs., K trifluororoborate salts, N-BOC amines, and aryl derivatives by C-BPin to C-aryl transformation. The results came from multiple reactions, including the reaction of Methyltriphenylphosphonium bromide(cas: 1779-49-3Product Details of 1779-49-3)
Methyltriphenylphosphonium bromide(cas: 1779-49-3) is an organophosphorus compound, with potential use as a precursor and a solvent in organic synthesis. And it is used widely for methylenation via the Wittig reaction.Product Details of 1779-49-3
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary