- A Boron Activating Effect Enables Cobalt-Catalyzed Asymmetric Hydrogenation of Sterically Hindered Alkenes
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Unsymmetric 1,1-diboryl alkenes bearing one -[BPin] (BPin = pinacolatoboryl) and one -[BDan] (BDan = 1,8-diaminonaphthalatoboryl) substituent each were hydrogenated in high yield and enantioselectivity using C1-symmetric pyridine(diimine) (PDI)
- Chirik, Paul J.,Krautwald, Simon,Pabst, Tyler P.,Viereck, Peter
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supporting information
p. 3923 - 3930
(2020/03/10)
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- New method for preparing asymmetric boron reagent Bpin-Bdan
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The invention relates to a new method for preparing an asymmetric boron reagent Bpin-Bdan. The method comprises: placing a magnetic stirrer in a reaction bottle, sequentially adding bis(pinacolato)diboron, 1,8-diaminonaphthalene and sodium methoxide, carrying out nitrogen suction replacement three times, adding a solvent methanol under a nitrogen stream, carrying out reaction heating to a temperature of 70 DEG C, stirring for 4 h, carrying out rotary evaporation to remove the solvent toluene after completing the reaction, and separating with column chromatography to obtain the asymmetric diboronation reagent Bpin-Bdan. According to the present invention, the use of the expensive raw material and the cumbersome experimental operation are eliminated, and the reaction temperature is reduced, such that the asymmetric boron reagent Bpin-Bdan preparation cost is substantially reduced, and the application of the asymmetric boron reagent Bpin-Bdan is broad.
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Paragraph 0012
(2017/09/01)
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- Unsymmetrical 1,1-diborated multisubstituted sp3-carbons formed via a metal-free concerted-asynchronous mechanism
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We have experimentally proved the unsymmetrical 1,1-diboration of diazo compounds, formed in situ from aldehydes and cyclic and non-cyclic ketones, in the absence of any transition metal complex. The heterolytic cleavage of the mixed diboron reagent, Bpin-Bdan, and the formation of two geminal C-Bpin and C-Bdan bonds has been rationalised based on DFT calculations to occur via a concerted-asynchronous mechanism. Diastereoselection is attained on substituted cyclohexanones and DFT studies provide understanding on the origin of the selectivity. The alkoxide-assisted selective deborylation of Bpin from multisubstituted sp3-carbon and generation of a Bdan stabilized carbanion, easily conducts a selective protodeboronation sequence.
- Cuenca, Ana B.,Cid, Jessica,García-López, Diego,Carbó, Jorge J.,Fernández, Elena
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supporting information
p. 9659 - 9664
(2015/09/28)
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- Mixed diboration of alkenes in a metal-free context
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Experimental and theoretical rationalization on regioselective mixed diboration of alkenes, with the unsymmetrical diboron reagent Bpin-Bdan, providing the protecting Bdan moiety in the internal position.
- Miralles, Nuria,Cid, Jessica,Cuenca, Ana B.,Carbó, Jorge J.,Fernández, Elena
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supporting information
p. 1693 - 1696
(2015/03/05)
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- A masked diboron in Cu-catalysed borylation reaction: Highly regioselective formal hydroboration of alkynes for synthesis of branched alkenylborons
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The use of a masked diboron as a boron source in the presence of a Cu-N-heterocyclic carbene (NHC) catalyst enables alkyl-, aryl-, heteroatom- and silyl-substituted terminal alkynes to undergo α-selective formal hydroboration to give diverse branched alkenylboron compounds exclusively. Synthetic potential of this α-selective hydroboration has been demonstrated by total synthesis of pharmaceutically significant bexarotene and LG100268. This journal is the Partner Organisations 2014.
- Yoshida, Hiroto,Takemoto, Yuki,Takaki, Ken
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supporting information
p. 8299 - 8302
(2014/07/22)
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