- 1-Methyl-1H-tetrazol-5-yl (MT) sulfones in the Julia-Kocienski olefination: Comparison with the PT and the TBT sulfones
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The stability and the stereoselectivity of newly prepared n-pentyl 1-methyl-1H-tetrazol-5-yl (MT) sulfone 1a in the Julia-Kocienski reactions were compared with those of the PT sulfone 1b and the TBT sulfone 1c. The improved stability of the anion derived from the n-pentyl MT sulfone 1a enhanced the efficiency of the olefination reactions and gave higher yields of the product alkenes 3 compared with the PT sulfone 1b. Especially high E-selectivity and high yields were obtained from the reaction with aromatic aldehydes and α,β-unsaturated aldehydes. The selectivity of 1a was not so sensitive to the change of base counter ion compared with the PT sulfone 1b. The reaction of the MT sulfones having either ethyl or a longer alkyl chain also gave E-alkenes selectively in high yields.
- Ando, Kaori,Kawano, Daiki,Takama, Daiki,Semii, Yutaka
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p. 1566 - 1569
(2019/05/22)
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- MIDA-Vinylsilanes: Selective Cross-Couplings and Applications to the Synthesis of Functionalized Stilbenes
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(Chemical Equation Presented). A rapid and stereodefined synthesis of MIDA-boryl vinylsilanes has been achieved through the hydrosilylation of an alkynylboronic ester. The E products which contain a silyl and boryl group can be selectively cross-coupled i
- McLaughlin, Mark G.,McAdam, Catherine A.,Cook, Matthew J.
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supporting information
p. 10 - 13
(2015/07/28)
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- Base-dependent formation of cis and trans olefins and their application in the synthesis of 5-oxo-ETE receptor antagonists
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5-Oxo-ETE is the most potent eosinophil chemoattractant among lipid mediators. We have developed two 5-oxo-ETE receptor antagonists. In the course of the work, we have developed a procedure to selectively introduce a cis and trans double bond in an alkyl side chain. Reacting indolecarboxaldehydes with alkyl ylides using the Li base affords the trans olefins, whereas using the K base yields the cis olefins.
- Gore, Vivek,Chourey, Shishir,Ye, Qiuji,Patel, Pranav,Ouedraogo, Yannick,Gravel, Sylvie,Powell, William S.,Rokach, Joshua
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p. 3385 - 3388
(2014/07/22)
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- Catalytic features of the reaction of oxidative cross-coupling of styrene and hexene-1
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The reaction of oxidative cross-coupling of styrene and hexene-1 in the medium of ice acetic acid was studied in the presence of various active phases based on palladium deposited on carbon-containing carrying agents, activated carbon, fullerenes, astrale
- Grisha,De Vekki
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body text
p. 407 - 412
(2012/08/08)
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- Oxidative cross-coupling of styrene and 1-hexene in acetoxylation reaction conditions
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Reaction of heterogeneous-catalytic coupling of styrene and 1-hexene in glacial acetic acid was studied for the first time.
- Grisha,De Vekki
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experimental part
p. 1903 - 1908
(2012/03/12)
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- Stereoselective synthesis of unsymmetrical conjugated dienes and trienes utilizing silacyclobutenes
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Treatment of the different kinds of alkynyl-substituted dialkynyldiarylsilanes with zirconocene-ethylene complex Cp2Zr(CH2{double bond, long}CH2) followed by acidification with 3 N HCl gave regio- and stereoselectively the
- Jin, Chung Keun,Yamada, Toshiaki,Sano, Shigeki,Shiro, Motoo,Nagao, Yoshimitsu
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p. 3671 - 3675
(2008/02/03)
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- Oxidative palladium(II) catalysis: A highly efficient and chemoselective cross-coupling method for carbon-carbon bond formation under base-free and nitrogenous-ligand conditions
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We report herein the development of a general and mild protocol of oxygen-promoted Pd(II) catalysis resulting in the selective cross-couplings of alkenyl- and arylboron compounds with various olefins. Unlike most cross-coupling reactions, this new methodology works well even in the absence of bases, consequently averting undesired homo-couplings. Nitrogen-based ligands including dimethyl-phenanathroline enhance reactivities and offer a highly efficient and stereoselective methodology to overcome challenging substrate limitations. For instance, oxidative palladium(II) catalysis is effective with highly substituted alkenes and cyclic alkenes, which are known to be incompatible with other known catalytic conditions. Most examined reactions progressed smoothly to completion at low temperatures and in short times. These interesting results provide mechanistic insights and utilities for a new paradigm of palladium catalytic cycles without bases.
- Yoo, Kyung Soo,Yoon, Cheol Hwan,Jung, Kyung Woon
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p. 16384 - 16393
(2007/10/03)
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- Oxygen-promoted palladium(II) catalysis: Facile C(sp2)-C(sp 2) bond formation via cross-coupling of alkenylboronic compounds and olefins
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(Chemical Equation Presented) Oxygen-promoted Pd(II) catalysis facilitated the synthesis of conjugated dienes by cross-coupling of alkenylboronic compounds and various olefins including highly substituted alkenes and cyclohexenone. Under mild conditions, these versatile reactions were efficient and highly stereoselective.
- Cheol, Hwan Yoon,Kyung, Soo Yoo,Sung, Wook Yi,Mishra, Rajesh K.,Kyung, Woon Jung
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p. 4037 - 4039
(2007/10/03)
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- Cobalt(I)-catalyzed stereoselective olefination of alkylzinc reagents with aldehydes
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The efficient olefination from organozinc reagents with aldehydes is exploited in a new synthesis of aryl and alkyl olefins.
- Wang, Jin-Xian,Fu, Ying,Hu, Yulai,Wang, Kehu
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p. 1506 - 1510
(2007/10/03)
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- Polymer-bound palladium-catalyzed cross-coupling of organoboron compounds with organic halides and organic triflates
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The polymer-bound palladium-catalyzed cross-coupling reaction of electrophiles (i.e., halides and triflates) with oganoboron compounds to form carbon-carbon bonds was achieved at mild conditions with very high activity in the Suzuki coupling reaction. The polymeric catalyst can be easily separated from a reaction mixture and reused more than 10 times with no decrease in activity.
- Jang, Su-Bum
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p. 1793 - 1796
(2007/10/03)
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- Cross-coupling and carbonylative cross-coupling of organofluorosilanes with hypervalent iodonium tetrafluoroborates
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The palladium-catalyzed cross-coupling and carbonylative cross-coupling of aryl-, alkenyl-, and alkynylfluorosilanes promoted by fluoride ion with hypervalent aryl-, alkenyliodonium tetrafluoroborates were achieved at room temperature under an atmospheric pressure of carbon monoxide.
- Kang, Suk-Ku,Yamaguchi, Tokutaro,Hong, Ryung-Kee,Kim, Tae-Hyun,Pyun, Sung-Jae
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p. 3027 - 3034
(2007/10/03)
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- Novel and Convenient Method for the Stereo- and Regiospecific Synthesis of Conjugated Alkadienes and Alkenynes via the Palladium-Catalyzed Cross-Coupling Reaction of 1-Alkenylboranes with Bromoalkenes and Bromoalkynes
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Details of a new and general method for the stereo- and regiospecific synthesis of conjugated alkadienes and alkenynes are described.The reaction of (E)- or (Z)-1-alkenyldisiamylboranes, or 2-((E)-1-alkenyl)-1,3,2-benzodioxaboroles readily obtainable by hydroboration, with either (E)- or (Z)-1-alkenyl bromides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium and bases such as sodium alkoxides gives the corresponding (E,E)-, (E,Z)-, (Z,E)-,or (Z,Z)-conjugated alkadienes stereo- and regiospecifically, while retaining the configurations of both the strating alkenylboranes and bromoalkenes.The reaction of (E)- and (Z)-1-alkenyldisiamylboranes with 1-bromoalkynes similarly provides a stereo- and regiospecific synthesis of conjugated (E)- and (Z)-alkenynes.A mechanism of this cross-coupling reaction, which involves the transmetalation between a 1-alkenylborane and an alkoxypalladium(II) complex generated through the metathetical displacement of a halogen atom from R(Pd(II)X with sodium alkoxide, is proposed.
- Miyaura, Norio,Yamada, Kinji,Suginome, Hiroshi,Suzuki, Akira
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p. 972 - 980
(2007/10/02)
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- A Synthesis of Conjugated Dienes from Aromatic, Five-membered Heterocycles
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Reactions of furan, thiophene, selenophene, and tellurophene as well as 2-methyl and 2,5-dimethyl derivatives of the first two heterocycles with phenyl-, methyl-, and n-butyl-magnesium bromides in the presence of ligated nickel dichloride are shown to yield buta-1,3-dienes mostly with retention of configuration.
- Wenkert, Ernest,Leftin, Michael H.,Michelotti, Enrique L.
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p. 617 - 618
(2007/10/02)
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- Chemical process
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Novel 2,4-dihydrocarbylspiro[5.5]undeca-1,4,8-trien-3-one compounds are prepared by reacting an N,N-dihydrocarbyl,2,6-dihydrocarbyl-4-aminomethylphenol with a conjugated diene and an alkyl halide in a liquid solvent medium.
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- A STEREOSPECIFIC SYNTHESIS OF CONJUGATED (E,Z)- AND (Z,Z)-ALKADIENES BY A PALLADIUM-CATALYZED CROSS-COUPLING REACTION OF 1-ALKENYLBORANES WITH 1-ALKENYL BROMIDES
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The reactions of (Z)-1-alkenyldisiamylboranes with (Z)- or (E)-1-alkenyl bromides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium and sodium ethoxide gave the corresponding conjugated (Z,Z)- or (Z,E)-alkadiene with high ster
- Miyaura, Norio,Suginome, Hiroshi,Suzuki, Akira
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p. 127 - 130
(2007/10/02)
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- THE PALLADIUM-CATALYZED "HEAD-TO-TAIL" CROSS-COUPLING REACTION OF 1-ALKENYLBORANES WITH PHENYL OR 1-ALKENYL IODIDES. A NOVEL SYNTHESIS OF 2-PHENYL-1-ALKENES OR 2-ALKYL-1,3-ALKADIENES VIA ORGANOBORANES
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The reaction of phenyl or 1-alkenyl iodides with 1-alkenyl-1,3,2-benzodioxaboroles readily obtainable via the hydroboration of 1-alkynes, gives the corresponding "head-to-tail" cross-coupling products, 2-phenyl-1-alkenes or 2-alkyl-1,3-alkadienes, in good yields.The reaction is effectively catalyzed by catalytic amounts of palladium compounds in the presence of triethylamine.
- Miyaura, Norio,Suzuki, Akira
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p. C53 - C56
(2007/10/02)
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