6224-91-5Relevant articles and documents
γ-Carboline synthesis enabled by Rh(iii)-catalysed regioselective C-H annulation
Jiang, Bo,Jia, Jingwen,Sun, Yufei,Wang, Yichun,Zeng, Jing,Bu, Xiubin,Shi, Liangliang,Sun, Xiaoying,Yang, Xiaobo
supporting information, p. 13389 - 13392 (2020/11/10)
A redox-neutral Rh(iii)-catalyzed C-H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system. This journal is
Propargylic C(sp3)-H Bond Activation for Preparing η3-Propargyl/Allenyl Complexes of Yttrium
Nagae, Haruki,Kundu, Abhinanda,Tsurugi, Hayato,Mashima, Kazushi
, p. 3061 - 3067 (2017/09/05)
Propargylic C(sp3) - H bond activation of 1-substituted-1-propynes, such as 1-trimethylsilyl-1-propyne, 2-hexyne, and 1-phenyl-1-propyne, was achieved by treatment with an alkylyttrium complex 8 bearing an ene-diamido ligand to give the corresponding (η3-propargyl/allenyl)yttrium complexes 7a-c. A unique delocalized η3-propargyl/allenyl structure of these three complexes was revealed by NMR spectroscopy and X-ray single crystal analyses. To elucidate the reactivity of the η3-propargyl/allenyl unit of complexes 7a-c, we conducted two reactions with N-methylaniline and N,N′-dicyclohexylcarbodiimine. For protonation by N-methylaniline, we found that the product distribution of monosubstituted internal alkynes and allenes depended on the substituent on the η3-propargyl/allenyl moiety: 7a and 7b afforded the corresponding internal alkynes as the major products, whereas the major protonation product of 7c was phenylallene. For the insertion of N,N′-dicyclohexylcarbodiimine, complex 7a selectively yielded η3-{N,N′-dicyclohexyl-2-(3-trimethylsilylpropargyl)amidinate}yttrium 12a, while complex 7c produced η3-{N,N′-dicyclohexyl-2-(1-phenylallenyl)amidinate}yttrium complex 13c, though complex 7b gave a mixture of η3-{N,N′-dicyclohexyl-2-(3-normalpropylpropargyl)amidinate}yttrium complex 12b and η3-{N,N′-dicyclohexyl-2-(1-normalpropylallenyl)amidinate}yttrium 13b in an 83:17 ratio. On the basis of the product distributions in these two-types of reactions, (η3-propargyl/allenyl)yttrium complexes were shifted into preferentially favorable η1-allenyl species or η1-propargyl species depending on the substituents prior to the reaction with electrophiles via a four-membered cyclic mechanism.
Synthesis of 2,3-disubstituted indenones by cobalt-catalyzed [3+2] annulation of: O -methoxycarbonylphenylboronic acid with alkynes
Ueda, Mitsuhiro,Ueno, Tamami,Suyama, Yuki,Ryu, Ilhyong
supporting information, p. 13237 - 13240 (2016/11/17)
Treatment of alkynes with o-methoxycarbonylphenylboronic acid in the presence of a cobalt catalyst resulted in the corresponding 2,3-disubstituted indenones in good yields. Excellent regioselectivities were observed, when silyl aryl alkynes were used. The intermediate 3-silyl-2-aryl-substituted indenones were converted to 2,3-diaryl indenones by a three-step protocol involving C-Si bromination and Suzuki-Miyaura coupling reaction.
Preparative synthesis via continuous flow of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane: A general propargylation reagent
Fandrick, Daniel R.,Roschangar, Frank,Kim, Chunyoung,Hahm, Byoung J.,Cha, Myoung H.,Kim, Hyoun Y.,Yoo, Gyesang,Kim, Taeyun,Reeves, Jonathan T.,Song, Jinhua J.,Tan, Zhulin,Qu, Bo,Haddad, Nizar,Shen, Sherry,Grinberg, Nelu,Lee, Heewon,Yee, Nathan,Senanayake, Chris H.
supporting information; scheme or table, p. 1131 - 1140 (2012/08/13)
A scalable process for the preparation of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane from trimethylsilylpropyne, isopropyl pinacol borate, and n-butyllithium is described. Problems associated with implementing a typical aqueous workup and batch process into production due to borolane ate equilibration and protonolysis are presented. To address these issues, a continuous-flow and distillation process was developed which efficiently produced 297 kg of the key propargylation reagent.
Regioselective allene synthesis and propargylations with propargyl diethanolamine boronates
Fandrick, Daniel R.,Reeves, Jonathan T.,Tan, Zhulin,Lee, Heewon,Song, Jinhua J.,Yee, Nathan K.,Senanayake, Chris H.
scheme or table, p. 5458 - 5461 (2010/03/01)
"Chemical Equation Presented" The utility of propargyl diethanolamine boronates as reagents for the preparation of allenes and homopropargylic alcohols is presented. Protonolysis with TFA and electrophilic substitution with N-halosuccinimides proceeded wi
Unique σ-bond metathesis of silylalkynes promoted by an ansa-dimethylsilyl and oxo-bridged uranium metallocene
Wang, Jiaxi,Gurevich, Ylia,Botoshansky, Mark,Eisen, Moris S.
, p. 9350 - 9351 (2007/10/03)
The tetrachloride salt of uranium reacts with 1 equiv of the lithium ligand Li2[(C5Me4)2SiMe2] in DME to form the complex [η5-(C5Me4)2SiMe2]UCl2·2LiCl·2DME (1), which undergoes a rapid hydrolysis in toluene to yield the dimeric bridged monochloride, monooxide complex [{[η5-(C5Me4)2SiMe2]UCl}2(μ-O)(μ-Cl)?Li?1/2DME]2 (2). Metathesis of 2 with BuLi in DME gives the mono-bridged dibutyl complex {[η5-(C5Me4)2SiMe2]UBu}2(μ-O) (3). Complex 2 was characterized by solid-state X-ray analysis. Complex 3 was found to be an active catalyst for the disproportionation metathesis of TMSC≡CH (TMS = SiMe3) and the cross-metathesis of TMSC≡CH or TMSC≡CTMS with various terminal alkynes. The metathesis of TMSC≡CH gives TMSC≡CTMS and HC≡CH, whereas the cross-metathesis of TMSC≡CH or TMSC≡CTMS with terminal alkynes (RC≡CH) yields TMSC≡CTMS, TMSC≡CR, and HC≡CH. In addition, TMSC≡CCH3 also was found to react with tBuC≡CH, yielding TMSC≡CBut and CH3C≡CH. A plausible mechanism for the catalytic process is presented. Copyright
Trimethylsilylated 1,4-Diborinanes and 1,3-Diborolanes - Formation, Isomer Separation, and Characterisation
Koester, Roland,Seidel, Guenter,Lutz, Frank,Krueger, Carl,Kehr, Gerald,Wrackmeyer, Bernd
, p. 813 - 820 (2007/10/02)
Me3SiCCH (A) reacts with excess (Et2BH)2 via the compounds 1, 1' and 2, 2' to yield a mixture of four regio- and stereoisomeric 1,4-diethyl-2,5(6)-bis(trimethylsilyl)-1,4-diborinanes (3a-d) and minor amounts of 1,3-diethyl-2-methyl-trans-2,5-bis(trimethylsilyl)-1,3-diborolane(4a).The 2,5-ee-(Me3Si)2 compound 3d is isolated as the adduct 3d(Pic)2 (X-ray structure analysis), from which pure 3d is obtained with Et2O-BF3. 3d and Me3P form equilibria of the 1:1 and 1:2 addition compounds 3d(Me3P)n (n = 1,2) at room temperature.Me3SiCCMe (B) reacts with (Et2BH)2 via 5 to give 6 - 10, and Me3SiCCSiMe3 (C) reacts with (Et2BH)2 to form the ring compounds 12 and 13 via the presumably threo/erythro mixture of 11a and b. - Key Words: Hydroboration of 1-alkinylsilanes / Ethyldiboranes(6) / Alkyl substituent exchanges, >BH-borane-catalysed / 1,4-Diborinanes, trimethylsilyl-substituted, isomers of / Lewisbase - 1,4-Diborinanes
A new route to α,β-unsaturated aldehydes using the condensation of trimethylsilyl β-trimethylsilyl enol ethers with aldehydes
Duhamel, Lucette
, p. 7745 - 7748 (2007/10/02)
β-Trimethylsilyl enol ethers 1 (Z) obtained from β-bromoenolethers 2 were condensed with aliphatic and aromatic aldehydes in the presence of a catalytic quantity of trimethylsilyl triflate leading to ethylenic aldehydes 3 (E) with good yields (79-90%).
