127-66-2Relevant articles and documents
Collision-induced fragmentation of ionized 3-phenyl-1-butyn-3-ol mediated by an intermediate proton-bound complex [3]
She,Tu,Song,Liu
, p. 1191 - 1192 (1996)
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Further chemistry of ruthenium alkenyl acetylide complexes: Routes to allenylidene complexes via a series of electrophilic addition reactions
Hall, Michael R.,Korb, Marcus,Moggach, Stephen A.,Low, Paul J.
, p. 2838 - 2853 (2020/10/02)
The methyl substituents in the cationic allenylidene complexes trans-[Ru{C=C=C(Me)R}Cl(dppe)2]OTf ([1a?f]OTf) are readily deprotonated to give the corresponding alkenyl acetylide complexes trans-[Ru{C=CC(=CH2)R}Cl(dppe)2] (3; R = Me (a), Ph (b), cC5H10 (c), 4-MeS-C6H4 (d), cC4H3S (e), cC5H4N (f)). Similar chemistry is also observed from [Ru{C=C=C(Me)Ph}(dppe)Cp*]PF6 ([2b]PF6) and [Ru{C=C=C(Me)(4-MeS-C6H4)}(dppe)Cp*]PF6([2b]PF6), chosen to broaden the reaction scope, giving [Ru{C= CC(=CH2)Ph}(dppe)Cp*] (4b) and [Ru{C=C=C(CH2)(4-MeS-C6H4)}(dppe)Cp*] (4d). In turn, reactions of 3b,d and 4b,d with the [BF4]? salt of the electrophilic tritylium [CPh3]+ cation give the functionalized allenylidene complexes trans-[Ru{C=C=C(CH2CPh3)R}Cl(dppe)2]BF4 ([5b,d]BF4) and [Ru{C=C=C(CH2CPh3)R}(dppe)Cp*]BF4 ([6b,d]BF4) formed by addition of the electrophile to the remote vinylic carbon (C(δ)). Although trans-[Ru{C=C=C(CH2CPh3)Me}Cl(dppe)2]BF4 ([5a]BF4) could not be successfully purified from reactions of 3a with [CPh3]BF4, deprotonation of the crude product gave the Zaitsev vinyl product trans-[Ru{C=CC(=CHCPh3)Me}Cl(dppe)2] (7a) in good yield. The initial cycloheptatrienyl adducts formed from reactions of 3b,d and 4b,d with the tropylium salt [C7H7]BF4 undergo a ring-contraction process in chloroform solutions upon exposure to air, to give the styrene-like products trans-[Ru{C=C=C(R)C(H)=CHPh}Cl(dppe)2]BF4 ([10b,d]BF4) and [Ru{C=C= C(R)C(H)=CHPh}(dppe)Cp*]BF4 ([11b,d]BF4), through what is believed to be a radical mechanism mediated by triplet oxygen.
Kinetic Resolution of Tertiary Propargylic Alcohols by Enantioselective Cu?H-Catalyzed Si?O Coupling
Seliger, Jan,Dong, Xichang,Oestreich, Martin
supporting information, p. 1970 - 1974 (2019/01/29)
A broad range of tertiary propargylic alcohols were kinetically resolved by catalyst-controlled enantioselective silylation. This non-enzymatic kinetic resolution is catalyzed by a Cu?H species and makes use of the commercially available precatalyst MesCu/(R,R)-Ph-BPE and a simple hydrosilane as the resolving reagent. Both alkyl,aryl- as well as dialkyl-substituted propargylic alcohols participate, and especially high selectivity factors are achieved when the alkyne terminus carries a TIPS group, which also enables facile post-functionalization in this position (s up to 207).
Cycloisomerization of Conjugated Allenones into Furans under Mild Conditions Catalyzed by Ligandless Au Nanoparticles
Zorba, Leandros,Kidonakis, Marios,Saridakis, Iakovos,Stratakis, Manolis
supporting information, p. 5552 - 5555 (2019/08/01)
Au nanoparticles supported on TiO2 (1 mol %) catalyze the quantitative cycloisomerization of conjugated allenones into furans under very mild conditions. The reaction rate is accelerated by adding acetic acid (1 equiv), but the acid does not participate in the protodeauration step as in the corresponding Au(III)-catalyzed transformation. The process is purely heterogeneous, allowing thus the recycling and reuse of the catalyst effectively in several runs.
