- Room-temperature Stille cross-couplings of alkenyltin reagents and functionalized alkyl bromides that possess β hydrogens
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This communication describes a significant expansion in the scope of Stille reactions of Csp3 -X electrophiles, specifically, that Pd/P(t-Bu)2Me catalyzes the room-temperature cross-coupling of a variety of functionalized, β-hydrogen-containing alkyl bromides with an array of alkenyltin reagents. The structure of the phosphine (P(t-Bu)2Me) is well suited for facilitating oxidative addition and avoiding β-hydride elimination, while the fluoride serves to activate the tin reagent for efficient transmetalation. Copyright
- Menzel, Karsten,Fu, Gregory C.
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- Catalytic Enantioselective Synthesis of Allylic Boronates Bearing a Trisubstituted Alkenyl Fluoride and Related Derivatives
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The first catalytic method for diastereo- and enantioselective synthesis of allylic boronates bearing a Z-trisubstituted alkenyl fluoride is disclosed. Boryl substitution is performed with either a Z- or E-allyldifluoride and is catalyzed by bisphosphine/
- Akiyama, Sota,Kubota, Koji,Mikus, Malte S.,Paioti, Paulo H. S.,Romiti, Filippo,Liu, Qinghe,Zhou, Yuebiao,Hoveyda, Amir H.,Ito, Hajime
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supporting information
p. 11998 - 12003
(2019/08/01)
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- Palladium-catalyzed direct functionalization of benzoxazoles with alkenyl iodides
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A straightforward procedure for the palladium-catalyzed direct functionalization of benzoxazoles with alkenyl iodides is described. The reactions employ a Pd(II)-precatalyst and use 'on water' conditions to achieve the ready union of a range of di- and tr
- Gerelle, Maria,Dalencon, Anne J.,Willis, Michael C.
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supporting information; experimental part
p. 1954 - 1957
(2012/05/07)
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- Iododesilylation of TIPS-, TBDPS-, and TBS-substituted alkenes in connection with the synthesis of amphidinolides B/D
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The C-Si bonds of triisopropylsilyl-substituted alkenes, 1,3-dienes, and related multifunctional substrates, as well as analogous C-TBDPS and C-TBS bonds, are readily and chemoselectively cleaved with NIS (or other sources of I+, such as N-iodo
- Sidera, Mireia,Costa, Anna M.,Vilarrasa, Jaume
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p. 4934 - 4937
(2011/11/29)
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- Catalytic enantioselective conjugate allylation of unsaturated methylidene ketones
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The use of unsaturated methylidene ketones in catalytic conjugate allylations allows a significant expansion in substrate scope and, with appropriate chiral ligands, occurs in a highly enantioselective fashion.(Figure Presented)
- Brozek, Laura A.,Sieber, Joshua D.,Morken, James P.
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supporting information; scheme or table
p. 995 - 997
(2011/05/15)
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- Synthesis and properties of seleno-analog MK-organic dye for photovoltaic cells prepared by CH functionalization reactions of selenophene derivatives
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C-H arylation and homocoupling reactions of 2-formylselenophene were carried out with a palladium catalyst. By using these coupling reactions a seleno-analog of MK dye MK-49, which is an organic dye molecule of a dye-sensitized solar cell (DSSC), was synt
- Tamba, Shunsuke,Fujii, Ryosuke,Mori, Atsunori,Hara, Kohjiro,Koumura, Nagatoshi
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p. 978 - 979
(2012/01/30)
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- Palladium-catalyzed carbene insertion and trapping with carbon nucleophiles
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Palladium catalysts are shown to catalyze the three-component coupling of vinyl halides, trimethylsilyldiazomethane. and stabilized carbon nucleophiles. The reaction is believed to proceed through a palladium-carbene intermediate LX(R)Pd=CHSiMe3 that undergoes migration of the vinyl substituent to the electrophilic carbene center to generate an ν3-allylpalladium intermediate. The allylpalladium intermediate is attacked by the carbon nucleophile to generate a vinylsilane product.
- Devine, Sean K. J.,Van Vranken, David L.
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supporting information; experimental part
p. 1909 - 1911
(2009/04/18)
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- Terminal alkynes from aldehydes via dehydrohalogenation of (Z)-1-iodo-1-alkenes with TBAF
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Terminal alkynes were prepared in near quantitative yields via dehydrohalogenation of (Z)-1-iodo-1-alkenes with tetrabutylammonium fluoride (TBAF) under mild conditions. The methodology was expanded to include a one-pot, direct synthesis of terminal alkynes from aldehydes without the necessity of isolating and purifying the intermediate iodoalkene.
- Beshai, Mira,Dhudshia, Bhartesh,Mills, Ryan,Thadani, Avinash N.
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supporting information; experimental part
p. 6794 - 6796
(2009/04/07)
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- Palladium-catalyzed carbene insertion into vinyl halides and trapping with amines
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Palladium is shown to catalyze the three-component coupling of vinyl halides, trimethytsilyldiazomethane, and amines to generate allylamines. The mechanism is believed to Involve formation of an R-Pd=CHSiMe3 intermediate that undergoes migratio
- Devine, Sean K. J.,Van Vranken, David L.
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p. 2047 - 2049
(2008/02/02)
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- A practical transformation of aldehydes into (E)-iodoalkenes with geminal dichromium reagents
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A catalytic cycle of a chromium salt in a stereoselective transformation of aldehydes to (E)-l-iodoalkenes using a geminal dichromium reagent, is assembled with zinc, Me3SiCl, and NaI in dioxane.
- Takai, Kazuhiko,Ichiguchi, Tetsuya,Hikasa, Shintaro
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p. 1268 - 1270
(2007/10/03)
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- Stereoselective hydrogenolysis of 1,1-dibromo-1-alkenes and stereospecific synthesis of conjugated (Z)-alkenyl compounds
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The Pd-catalyzed hydrogenolysis of 1,1-dibromoalkenes with Bu3SnH occurs at room temperature stereoselectively to give (Z)-1-bromo-1-alkenes. We sought to determine the optimal reaction conditions and illustrate the scope of this method with 32 dibromoalkenes including alkenyl- and alkynyl- conjugated 1,1-dibromo-1-alkenes 7a-h and 2,2-disubstituted 1,1-dibromo-1- alkenes 9af. Triphenylphosphine was the best ligand for the Pd-catalyzed hydrogenolysis. A wide range of solvents can be used for this reaction excluding EtOH, AcOH, and CHCl3. However, the reaction proceeds even in these solvents with the addition of a cosolvent or radical scavenger. The reaction of 1,1-diiodo-1-alkene (3) gave a mixture of (Z)-1-iodo-1-alkene (4), (Z)-1-tributylstannyl-1-alkene (5), and a terminal alkene 6, while that of 1,1-dichloroalkene did not occur. This selectivity can be explained by the stereoselective insertion of Pd(0) to a trans bromine-alkenyl carbon bond, successive transmetalation with Bu3SnH, and reductive elimination. The Suzuki and Sonogashira couplings of the resulting (Z)-1-bromo-1-alkenes with alkenyl(dialkoxy)borane and terminal alkyne occurred to give conjugated polyenes and enynes stereospecifically. The Pd-catalyzed hydrogenolysis of 1,1-dibromo-1-alkene and successive cross-coupling can be carried out either in a stepwise manner or in one-pot under the same Pd catalysis. These two processes should be useful for the synthesis of geometrically pure polyene and enyne with a Z-alkenyl unit.
- Uenishi, Jun'ichi,Kawahama, Reiko,Yonemitsu, Osamu,Tsuji, Jiro
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p. 8965 - 8975
(2007/10/03)
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- Palladium-catalysed hydrostannylations of 1-bromoalkynes. A practical synthesis of (E)-1-stannylalk-1-enes
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A practical synthesis of (E)-1-stannylalk-1-enes containing a range of oxygen and nitrogen functionality is highlighted, involving hydrostannylation followed by palladium-catalysed carbon-bromine bond cleavage reactions of 1-bromoalkynes.
- Boden, Christopher D. J.,Pattenden, Gerald,Ye, Tao
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p. 2417 - 2419
(2007/10/03)
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