75659-04-0Relevant articles and documents
Asymmetric Intra- and Intermolecular Hydroamination Catalyzed by 3,3′-Bis(trisarylsilyl)- and 3,3′-Bis(arylalkylsilyl)-Substituted Binaphtholate Rare-Earth-Metal Complexes
Nguyen, Hiep N.,Lee, Hyeunjoo,Aud?rsch, Stephan,Reznichenko, Alexander L.,Nawara-Hultzsch, Agnieszka J.,Schmidt, Bernd,Hultzsch, Kai C.
, p. 4358 - 4379 (2018/09/27)
The series of novel 3,3′-bis(trisarylsilyl)- and 3,3′-bis(arylalkylsilyl)-substituted binaphtholate rare-earth-metal complexes 2a-i (SiR3 = Si(o-biphenylene)Ph (a), SiCyPh2 (b), Si-t-BuPh2 (c), Si(i-Pr)3 (d), SiCy2Ph (e), Si(2-tolyl)Ph2 (f), Si(4-t-Bu-C6H4)3 (g), Si(4-MeO-C6H4)Ph2 (h), SiBnPh2 (i)) have been prepared via arene elimination from [Ln(o-C6H4CH2NMe2)3] (Ln = Y, Lu) and the corresponding 3,3′-bis(silyl)-substituted binaphthol. The complexes exhibit high catalytic activity in the hydroamination/cyclization of aminoalkenes, with activities exceeding 1000 h-1 for (R)-2f-Ln, (R)-2g-Ln, and (R)-2h-Ln in the cyclization of 2,2-diphenylpent-4-enylamine (3a) at 25 °C, while the rigid dibenzosilole-substituted complexes (R)-2a-Ln and the triisopropylsilyl-substituted complexes (R)-2d-Ln exhibited the lowest activity in the range of 150-270 h-1. Catalysts (R)-2b-Lu, (R)-2c-Lu, (R)-2f-Lu, and (R)-2i-Lu provide the highest selectivities for the majority of the substrates, while the yttrium congeners are usually less selective. The highest enantioselectivities of 96% ee were observed using (R)-2a-Lu and (R)-2c-Lu in the cyclization of (4E)-2,2,5-triphenylpent-4-enylamine (9). The reactions show apparently zero-order rate dependence on substrate concentration and first-order rate dependence on catalyst concentration, with some reactions exhibiting a slightly accelerated rate at high conversion due to a shift in the equilibrium between a less active, higher coordinate catalyst species in favor of a more active, lower coordinate species as a result of weaker binding of the hydroamination product in comparison to the aminoalkene substrate. The shift in equilibrium from the higher to the lower coordinate species is also entropically favored at elevated temperatures, which results in an unusual increase in selectivity in the cyclization of 2,2-dimethylpent-4-enylamine (3d), presumably due to a higher selectivity of the lower coordinate catalyst species. All binaphtholate yttrium complexes, except (R)-2a-Y, are catalytically active in the intermolecular hydroamination of benzylamines with terminal alkenes. The highest selectivity of 66% ee was observed for the reaction of benzylamine with 4-phenyl-1-butene using (R)-2h-Y at 110 °C.
Asymmetric intermolecular hydroamination of unactivated alkenes with simple amines
Reznichenko, Alexander L.,Nguyen, Hiep N.,Hultzsch, Kai C.
supporting information; experimental part, p. 8984 - 8987 (2011/02/21)
A hard nut to crack: The asymmetric intermolecular Markovnikov addition of simple amines to unactivated alkenes can be achieved utilizing binaphtholate rare-earth-metal catalysts with up to 61% ee and 73% de in the case where R 2 contains a stereogenic center.
1,1′-Binaphthyl-2,2′-diyl phosphoroselenoyl chloride as a chiral molecular tool for the preparation of enantiomerically pure alcohols and amines
Murai, Toshiaki,Matsuoka, Daichi,Morishita, Ken
, p. 4584 - 4585 (2007/10/03)
Enantiomerically pure phosphoroselenoyl chloride bearing a binaphthyl group was synthesized. This phosphoroselenoyl chloride was used to discriminate and resolve simple secondary alcohols. Stereospecific conversions of diastereomerically pure phosphoroselenoic acid esters, obtained by reaction of the chloride with simple secondary alcohols, to enantiomerically pure alcohols and amines were also achieved. Copyright
