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All total 66 Articles be found
All total 66 Articles be foundIridium-catalyzed diborylation of benzylic C-H bonds directed by a hydrosilyl group: Synthesis of 1,1-benzyldiboronate esters
Cho, Seung Hwan,Hartwig, John F.
, p. 694 - 698 (2014)
We describe a regioselective diborylation of primary benzylic C-H bonds catalyzed by [Ir(COD)OMe]2 and 4,4′-di-tert-butyl-2,2′- bipyridine (dtbpy). The hydrosilyl group acts as a traceless directing group, providing access to a range of 1,1-benzyldiboronate esters in good yields. Transformations of the 1,1-benzyldiboronate ester products include chemoselective Suzuki-Miyaura cross-couplings and synthesis of tetrasubstituted alkenyl boronate esters.
Opportune gem-Silylborylation of Carbonyl Compounds: A Modular and Stereocontrolled Entry to Tetrasubstituted Olefins
La Cascia, Enrico,Cuenca, Ana B.,Fernández, Elena
, p. 18737 - 18741 (2016)
An easy access to highly versatile gem-silylboronate synthons is achieved by means of a new olefination reagent, HC(Bpin)2(SiMe3). Subsequent silicon or boron-based selective functionalization allows for the modular and stereocontrolled synthesis of all-carbon tetrasubstituted alkenes. A particular attraction of this approach is the iododesilylation reaction, which becomes a pivotal tool for C?Si functionalization.
An atom efficient synthesis of tamoxifen
Heijnen, Dorus,Van Zuijlen, Milan,Tosi, Filippo,Feringa, Ben L.
, p. 2315 - 2320 (2019)
The direct carbolithiation of diphenylacetylenes and their cross-coupling procedure taking advantage of the intermediate alkenyllithium reagents are presented. By employing our recently discovered highly active palladium nanoparticle based catalyst, we were able to couple an alkenyllithium reagent with a high (Z/E) selectivity (10:1) and good yield to give the breast cancer drug tamoxifen in just 2 steps from commercially available starting materials and with excellent atom economy and reaction mass efficiency.
Stereoselective synthesis of trisubstituted alkenylboranes by palladium-catalysed reaction of alkynyltriarylborates with aryl halides
Ishida, Naoki,Miura, Tomoya,Murakami, Masahiro
, p. 4381 - 4383 (2007)
The palladium-catalysed reaction of alkynyltriarylborates with aryl halides afforded trisubstituted alkenylboranes, in which two different aryl groups were installed across the carbon-carbon double bond in a cis arrangement. The Royal Society of Chemistry.
Stereoconvergent and -divergent synthesis of tetrasubstituted alkenes by nickel-catalyzed cross-couplings
Zell, Daniel,Kingston, Cian,Jermaks, Janis,Smith, Sleight R.,Seeger, Natalie,Wassmer, Jana,Sirois, Lauren E.,Han, Chong,Zhang, Haiming,Sigman, Matthew S.,Gosselin, Francis
supporting information, p. 19078 - 19090 (2021/11/22)
We report the development of a method to diastereoselectively access tetrasubstituted alkenes via nickel-catalyzed Suzuki-Miyaura cross-couplings of enol tosylates and boronic acid esters. Either diastereomeric product was selectively accessed from a mixture of enol tosylate starting material diastereomers in a convergent reaction by judicious choice of the ligand and reaction conditions. A similar protocol also enabled a divergent synthesis of each product isomer from diastereomerically pure enol tosylates. Notably, high-throughput optimization of the monophosphine ligands was guided by chemical space analysis of the kraken library to ensure a diverse selection of ligands was examined. Stereoelectronic analysis of the results provided insight into the requirements for reactive and selective ligands in this transformation. The synthetic utility of the optimized catalytic system was then probed in the stereoselective synthesis of various tetrasubstituted alkenes, with yields up to 94% and diastereomeric ratios up to 99:1 Z/E and 93:7 E/Z observed. Moreover, a detailed computational analysis and experimental mechanistic studies provided key insights into the nature of the underlying isomerization process impacting selectivity in the cross-coupling.
NOVEL TRIBORYLALKENE, PRODUCTION METHOD THEREOF, AND PRODUCTION METHOD OF MULTISUBSTITUTED ALKENE
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Paragraph 0206, (2020/03/10)
PROBLEM TO BE SOLVED: To provide a compound as a synthetic intermediate for a tetraarylalkene useful as medicaments and electronic materials. SOLUTION: The invention provides a triborylalkene represented by the general formula (I) in the figure, where Ra represents an optionally substituted aryl group. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
