791845-43-7Relevant academic research and scientific papers
Copper(ii)-catalyzed protoboration of allenes in aqueous media and open air
Nekvinda, Jan,Santos, Webster L.,Snead, Russell F.
, p. 14925 - 14931 (2021/09/04)
A method has been developed for the facile Cu(ii)-catalyzed protoboration of monosubstituted allenes in aqueous media under atmospheric conditions. The reaction occurs site selectively, favoring internal alkene protoboration to afford 1,1-disubstituted vinylboronic acid derivatives (up to 93?:?7) with modest to good yields. The method has been applied to a variety of phenylallene derivatives as well as alkyl-substituted allenes. This journal is
NHC-Cu-catalyzed protoboration of monosubstituted allenes. Ligand-controlled site selectivity, application to synthesis and mechanism
Meng, Fanke,Jung, Byunghyuck,Haeffner, Fredrik,Hoveyda, Amir H.
supporting information, p. 1414 - 1417 (2013/04/23)
Two types of NHC-Cu complexes catalyze protoborations of terminal allenes to afford valuable 1,1- or trisubstituted vinylboron species with high site selectivity and stereoselectivity. The scope of the method, application to natural product synthesis, and
Diastereodivergent synthesis of trisubstituted alkenes through protodeboronation of allylic boronic esters: Application to the synthesis of the californian red scale beetle pheromone
Hesse, Matthew J.,Butts, Craig P.,Willis, Christine L.,Aggarwal, Varinder K.
supporting information, p. 12444 - 12448 (2013/02/23)
E-allylic boronic esters undergo a highly diastereoselective protodeboronation with TBAF·3 H2O to give Z-trisubstituted alkenes. The selectivity can be switched to give predominantly the E-alkene instead by using KHF2/TsOH (see scheme). The utility of the methodology has been illustrated in a short synthesis of a component of the sex pheromone of the Californian red scale beetle. Copyright
Regiocontrolled CuI-catalyzed borylation of propargylic- functionalized internal alkynes
Moure, Abraham L.,Gomez Arrayas, Ramon,Cardenas, Diego J.,Alonso, Ines,Carretero, Juan C.
supporting information; experimental part, p. 7219 - 7222 (2012/06/16)
Good to excellent reactivity and regiocontrol have been achieved in the CuI-catalyzed borylation of dialkyl internal alkynes with bis(pinacolato)diboron. The presence of a propargylic polar group (OH, OR, SAr, SO2Ar, or NHTs), in combination with PCy3 as ligand, allowed maximizing the reactivity and site-selectivity (β to the propargylic function). DFT calculations suggest a subtle orbitalic influence from the propargylic group, matched with ligand and substrate size effects, as key factors involved in the high β-selectivity. The vinylboronates allowed the stereoselective synthesis of trisubstituted olefins, while allylic substitution of the SO2Py group without affecting the boronate group provided access to formal hydroboration products of unbiased dialkylalkynes.
Copper-catalyzed highly regio- and stereoselective directed hydroboration of unsymmetrical internal alkynes: Controlling regioselectivity by choice of catalytic species
Semba, Kazuhiko,Fujihara, Tetsuaki,Terao, Jun,Tsuji, Yasushi
supporting information; experimental part, p. 4179 - 4184 (2012/05/31)
A highly selective synthesis of the αand β products by copper-catalyzed hydroboration utilizing two different catalytic copper species generated from pinacolborane (HBpin) and B2pin2 is reported. Regioselectivity in the crude reaction mixtures is found to be high, and the corresponding a products were isolated in good yields. In the case of an alkyne containing an alkenyl moiety, the regioselectivity decreased to 72:28. In hydroboration reactions catalyzed by other transition metals, selecting between hydrometalation and boryl metalation is difficult because the oxidative addition of HB to a metal center provides an H-M-B species, containing both H-M and B-M bonds. The α and β products are valuable intermediates used in the Suzuki-Miyaura cross-coupling reaction to regioselectively prepare various trisubstituted alkenes of types 5α and 5β.
