4286-85-5Relevant articles and documents
Titanocene(II)-promoted stereoselective alkenylation utilizing (Z)-alkenyl sulfones
Ogata, Akitoshi,Nemoto, Masami,Kobayashi, Kenji,Tsubouchi, Akira,Takeda, Takeshi
, p. 3816 - 3822 (2007)
(Chemical Equation Presented) The stereoselective alkenylation of unsaturated compounds by means of a (Z)-alkenyl sulfone-titanocene-(II) system is described. Treatment of alkynes and (Z)-alkenyl methyl sulfones with the titanocene(II) reagent Cp2Ti[P(OEt)3]2 produced conjugated dienes. This alkenylation system is also applicable to polar C=O bonds; the simple mixing of carbonyl compounds, (Z)-alkenyl methyl sulfones, and the titanocene-(II) reagent formed allylic alcohols. The advantages of alkenylation are that it requires no prepreparation of the alkenylmetal reagent and that it proceeds with complete stereoselectivity.
Facile Direct Coupling Reactions of MOM-protected Benzylic Alcohols Using Aluminum Chloride
Bui, Tien Tan,Kim, Hee-Kwon
supporting information, p. 1195 - 1198 (2021/08/03)
MOM group is one of the most commonly used protecting groups for alcohols. This study describes novel direct functionalization of the MOM-protected benzylic alcohols. Preparation of allylic compounds from benzyl MOM ethers was successfully achieved by utilization of allyltrimethylsilane and AlCl3. In addition, direct azidation of benzyl MOM ethers using TMSN3 was successful carried out under AlCl3-mediated reaction conditions. These results demonstrate that this novel synthetic procedure is a promising approach to direct functionalization of MOM-protected alcohols including allylation and azidation.
Direct AlCl3-catalyzed transformation of benzyl THP ethers and allyl benzyl ethers
Bui, Tien Tan,Kim, Hee-Kwon
, p. 388 - 397 (2020/10/15)
THP and allyl groups are frequently used for the protection of alcohols. In this study, novel direct transformations of benzyl THP ethers and allyl benzyl ethers, protected forms of alcohols, are reported. TMSN3 and AlCl3 were employ
Dual Nickel- And Photoredox-Catalyzed Reductive Cross-Coupling of Aryl Halides with Dichloromethane via a Radical Process
Xu, Tao,Xu, Wenhao,Zheng, Purui
supporting information, (2020/11/13)
The first catalytic strategy to harness a new chloromethane radical from dichloromethane under dual Ni/photoredox catalytic conditions has been developed. Compared with traditional two-electron reductive process associated with metallic reductants, this method via a single-electron approach can proceed under exceptionally mild conditions (visible light, ambient temperature, no strong base) and exhibits complementary reactivity patterns. It affords a broad scope of many functional groups, including alkenyl, which suffers cyclopropanation in previous routes. The diarylmethane-d2 compounds can be readily available with this transformation.
Arylboronic Acid Catalyzed C-Alkylation and Allylation Reactions Using Benzylic Alcohols
Estopi?á-Durán, Susana,McLean, Euan B.,Donnelly, Liam J.,Hockin, Bryony M.,Taylor, James E.
supporting information, p. 7547 - 7551 (2020/10/09)
The arylboronic acid catalyzed dehydrative C-alkylation of 1,3-diketones and 1,3-ketoesters using secondary benzylic alcohols as the electrophile is reported, forming new C-C bonds (19 examples, up to 98% yield) with the release of water as the only byproduct. The process is also applicable to the allylation of benzylic alcohols using allyltrimethylsilane as the nucleophile (12 examples, up to 96% yield).
Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis
Meng, Qing-Yuan,Schirmer, Tobias E.,Katou, Kousuke,K?nig, Burkhard
supporting information, p. 5723 - 5728 (2019/04/03)
We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.
Metal-free synthesis of gem -silylboronate esters and their Pd(0)-catalyzed cross-coupling with aryliodides
Wu, Chaoqiang,Bao, Zhicheng,Xu, Xing,Wang, Jianbo
, p. 5714 - 5724 (2019/06/18)
A transition-metal-free method for the synthesis of gem-silylboronate esters with arylboronic acids and trimethylsilyldiazomethane (TMSCHN2) has been developed. This transformation is a straightforward homologation of arylboronic acids and features wide substrate scope and good functional-group tolerance. The gem-silylboronate esters undergo efficient Suzuki-Miyaura cross-coupling with aryliodides and the silyl group of the product can be further functionalized. Tertiary carbon centers with different substituents can be constructed successfully by selective and sequential functionalization.
Rhenium complex-catalyzed carbon-carbon formation of alcohols and organosilicon compounds
Umeda, Rui,Jikyo, Toshifumi,Toda, Kazuki,Osaka, Issey,Nishiyama, Yutaka
supporting information, p. 1121 - 1124 (2018/02/21)
The coupling reactions of allylic and benzylic alcohols and allyltrimethylsilane are efficiently catalyzed by a rhenium complex to give the corresponding 1,5-dienes and alkenes in moderate to good yields. Similarly, alcohols were coupled with ketene silyl acetals to form the corresponding esters.
Testing the veracity of claims of Lewis acid catalysis
?oli?, Ivan,Lin, Hong Xuan,Bates, Roderick W.
supporting information, p. 4434 - 4436 (2018/11/23)
Are reactions employing Lewis acids really catalysed by those Lewis acids, or by “hidden Br?nsted acids”, i.e. Br?nsted acids generated in situ by hydrolysis? Testing of a series of reactions using Sc(III), Fe(III), In(III) and Y(III) by addition of 2,6-di-t-butyl-4-methylpyridine reveal that all are likely to follow the latter pathway. A reaction claimed to be catalysed by CBr4 through halogen bonding is also likely to be Br?nsted acid catalysed.
Silylated cyclopentadienes as competent silicon Lewis acid catalysts
Radtke, M. Alex,Lambert, Tristan H.
, p. 6406 - 6410 (2018/08/12)
The synthesis and characterization of silicon Lewis acid complexes that incorporate highly electron-deficient cyclopentadienes is reported. Several pentacarboxycyclopentadienyl and monocarboxytetracyanocyclopentadienyl complexes were prepared. A comparison of their reactivities for catalysis of the allylation of an electron-deficient benzaldehyde was established. The use of a monocarboxytetracyano silylium donor was shown to be effective for the allylation or arylation of a variety of electrophiles via an anion abstraction pathway.
