66377-63-7Relevant articles and documents
Stereoselective Synthesis of Carbobicyclics via Organoyttrium-Catalyzed Sequential Cyclization/Silylation Reactions
Molander, Gary A.,Nichols, Paul J.,Noll, Bruce C.
, p. 2292 - 2306 (1998)
The sequential cyclization/silylation of 1,5-dienes and 1,6-dienes was effected under mild reaction conditions using catalytic quantities of Cp2*YMe-THF. The process provides carbobicyclics in high yields and with excellent selectivities. The active catalyst is postulated to be Cp2*YH-THF, which is generated in situ. A variety of alkenyl-substituted cyclopentane and cyclohexane substrates were examined. The high diastereoselectivities apparently originate from a preference for a chairlike transition structure that minimizes unfavorable steric interactions between the bulky Cp* ligands of the catalyst and the preexisting ring of the substrate. Acyclic triene precursors, 4-ethenyl-substituted 1,5-heptadienes and 5-ethenyl-substituted 1,8-nonadienes were also examined. These triene substrates, when exposed to the cyclization/silylation protocol, provide the strained trans-bicyclo[3.3.0]octanes and trans-decalin systems in high yield with excellent diastereoselectivity. The high selectivity is again attributed to the preference for a chairlike transition structure. The cyclized organosilane products isolated from these reactions were easily converted to the more versatile alcohols utilizing known oxidation methods.
Palladium/TY-Phos-Catalyzed Asymmetric Intermolecular α-Arylation of Aldehydes with Aryl Bromides
Li, Wenbo,Liu, Feng,Pan, Zhangjin,Wu, Hai-Hong,Zhang, Junliang,Zhu, Shuai
supporting information, p. 18542 - 18546 (2021/07/21)
Despite much progress has been made in the asymmetric α-arylation reactions of cyclic ketones, lactones and lactams, the enantioselective α-arylation of acyclic carbonyl compounds lagged much behind due to the in situ generated Z/E-enolate intermediates l
Visible-Light-Mediated Anti-Markovnikov Hydration of Olefins
Hu, Xia,Zhang, Guoting,Bu, Faxiang,Lei, Aiwen
, p. 1432 - 1437 (2017/08/09)
Considering that stoichiometric borane and oxidant are required in the classical alkene anti-Markovnikov hydration process, it remains appealing to achieve the transformation in a catalytic protocol. Herein, a visible-light-mediated anti-Markovnikov addition of water to alkenes by using an organic photoredox catalyst in conjunction with a redox-active hydrogen atom donor was developed, which avoided the need for a transition-metal catalyst, stoichiometric borane, as well as oxidant. Both terminal and internal olefins are readily accommodated in this transformation to obtain corresponding primary and secondary alcohols in good yields with single regioselectivity. This procedure can be scaled up to gram scale with a 230 turnover number based on photocatalyst.