150766-59-9Relevant articles and documents
Tandem Iridium Catalysis as a General Strategy for Atroposelective Construction of Axially Chiral Styrenes
He, Ying,Liu, Peng,Min, Xiao-Long,Qi, Xiaotian,Wang, Jie,Yi, Wenbin
supporting information, p. 10686 - 10694 (2021/07/26)
Axially chiral styrenes are of great interest since they may serve as a class of novel chiral ligands in asymmetric synthesis. However, only recently have strategies been developed for their enantioselective preparation. Thus, the development of novel and efficient methodologies is highly desirable. Herein, we reported the first tandem iridium catalysis as a general strategy for the synthesis of axially chiral styrenes enabled by Asymmetric Allylic Substitution-Isomerization (AASI) using cinnamyl carbonate analogues as electrophiles and naphthols as nucleophiles. In this approach, axially chiral styrenes were generated through two independent iridium-catalytic cycles: iridium-catalyzed asymmetric allylic substitution and in situ isomerization via stereospecific 1,3-hydride transfer catalyzed by the same iridium catalyst. Both experimental and computational studies demonstrated that the isomerization proceeded by iridium-catalyzed benzylic C-H bond oxidative addition, followed by terminal C-H reductive elimination. Amid the central-to-axial chirality transfer, the hydroxyl of naphthol plays a crucial role in ensuring the stereospecificity by coordinating with the Ir(I) center. The process accommodated broad functional group compatibility. The products were generated in excellent yields with excellent to high enantioselectivities, which could be transformed to various axially chiral molecules.
Two-Step Synthesis of Unsymmetrical Diaryl Sulfides by Electrophilic Thiolation of Non-functionalized (Hetero)arenes
B?hm, Marvin J.,Golz, Christopher,Rüter, Isabelle,Alcarazo, Manuel
supporting information, p. 15026 - 15035 (2018/09/25)
This article reports the efficient preparation of a series of unsymmetrically substituted thioethers through a two-step procedure consisting of an initial metal-free C?H sulfenylation of electron-rich (hetero)arenes with newly prepared succinylthioimidazolium salts. Subsequent reaction of the arylthioimidazolium intermediates with Grignard reagents afford the desired thioethers. The synthetic protocol described is modular, scalable, and high yielding, and provides access to sulfides that are not easy to obtain through the existing methodologies. Importantly, no prefunctionalization of the initial (hetero)arene is required.
Nickel-Catalyzed Cross-Coupling of Redox-Active Esters with Boronic Acids
Wang, Jie,Qin, Tian,Chen, Tie-Gen,Wimmer, Laurin,Edwards, Jacob T.,Cornella, Josep,Vokits, Benjamin,Shaw, Scott A.,Baran, Phil S.
, p. 9676 - 9679 (2016/08/10)
A transformation analogous in simplicity and functional group tolerance to the venerable Suzuki cross-coupling between alkyl-carboxylic acids and boronic acids is described. This Ni-catalyzed reaction relies upon the activation of alkyl carboxylic acids as their redox-active ester derivatives, specifically N-hydroxy-tetrachlorophthalimide (TCNHPI), and proceeds in a practical and scalable fashion. The inexpensive nature of the reaction components (NiCl2?6 H2O—$9.5 mol?1, Et3N) coupled to the virtually unlimited commercial catalog of available starting materials bodes well for its rapid adoption.
Binding of aromatic molecules in the fullerene-rich interior of a fullerene bilayer vesicle in water
Harano, Koji,Gorgoll, Ricardo Mizoguchi,Nakamura, Eiichi
supporting information, p. 7629 - 7631 (2013/09/02)
Upon dissolution of R5C60-K+ in water, a robust spherical vesicle forms that binds aromatic molecules primarily in the interior of the fullerene bilayer, as illustrated by the complete quenching of the fluorescence of an aromatic fluorescent dye bound in the bilayer. The Royal Society of Chemistry.
Expanded substrate scope and improved reactivity of ether-forming cross-coupling reactions of organotrifluoroborates and acetals
Vo, Cam-Van T.,Mitchell, T. Andrew,Bode, Jeffrey W.
, p. 14082 - 14089 (2011/10/12)
Mixed acetals and organotrifluoroborates undergo BF3· OEt2-promoted cross-couplings to give dialkyl ethers under simple, mild conditions. A survey of reaction partners identified a hydroxamate leaving group that improves the regioselectivity and product yield in the BF 3·OEt2-promoted coupling reaction of mixed acetals and potassium alkynyl-, alkenyl-, aryl- and heteroaryltrifluoroborates to access substituted dialkyl ethers. This leaving group enables the reaction to proceed rapidly under mild conditions (0 °C, 5-60 min) and permits reactions with electron-deficient potassium aryltrifluoroborates that are less reactive with other acetal substrates. A study of the reaction mechanism and characterization of key intermediates by NMR spectroscopy and X-ray crystallography identified a role for the hydroxamate moiety as a reversible leaving group that serves to stabilize the key oxocarbenium intermediate and the need for a slight excess of organodifluoroborane to serve as a catalyst. A secondary role for the boron nucleophile as an activating ligand was also considered. These studies provide the basis for a general class of reagents that lead to dialkyl ethers by a simple, predictable cross-coupling reaction.
New strategies for protecting group chemistry: Synthesis, reactivity, and indirect oxidative cleavage of para-siletanylbenzyl ethers
Tlais, Sami F.,Lain, Hubert,House, Sarah E.,Dudley, Gregory B.
scheme or table, p. 1876 - 1885 (2009/07/01)
Reported herein is a new entry in the growing arsenal of arylmethyl ether protecting groups. The parasiletanylbenzyl (PSB) ether is electronically similar to the benzyl ether. Cleavage of the PSB ether is accomplished under mild conditions-involving alkaline hydrogen peroxide - that are unique among cleavage protocols for arylmethyl ethers. Furthermore, the PSB group affords the user new flexibility in the implementation of protecting group strategies that revolve around multiple arylmethyl ether protecting groups. In addition to hydrogen peroxide-based cleavage protocols, conversion of a PSB ether into a para-methoxybenzyl (PMB) ether and assembly of a PSB ether from a pre-existing para-bromobenzyl (PBB) ether are described. Finally, a new reagent for installing PSB ethers under neutral "mix and heat" conditions is reported.
Synthesis of dialkyl ethers from organotrifluoroborates and acetals
Mitchell, T. Andrew,Bode, Jeffrey W.
supporting information; experimental part, p. 18057 - 18059 (2010/03/26)
(Chemical Equation Presented) The formation of ethers by C-O bond formation under harsh basic or acidic conditions is an entrenched synthetic disconnection in organic chemistry. We report a strategic alternative that involves the BF3?OEt2
The para-siletanylbenzyl (PSB) ether: A peroxide-cleavable protecting group for alcohols and phenols
Lam, Hubert,House, Sarah E.,Dudley, Gregory B.
, p. 3283 - 3285 (2007/10/03)
A novel arylmethyl protecting group that is electronically similar to benzyl (Bn) but that can be cleaved under mild oxidizing conditions in the presence of para-methoxybenzyl (PMB) is described herein. para-Siletanylbenzyl (PSB) ethers are formed in one or two steps from the corresponding alcohols and cleaved in one or two steps with basic peroxide. Alcohols and phenols have been protected in good yields and deprotected cleanly under mild oxidative conditions.
Enantioselektive Katalyse. LXXXI. Optisch aktive Zweischalenphosphine
Brunner, H.,Fuerst, J.,Ziegler, J.
, p. 87 - 94 (2007/10/02)
Two-layer phosphines were synthesized by reaction of optically active bromotolyl and bromoxylyl derivates with PCl, and Cl2P-CH2-CH2-PCl2, respectively.The optically active bromotolyl and bromoxylyl ethers and amines were obtained from the corresponding b
