New Routes to Rare Aromatic BN-Heterocycles: 1,3-Azaborinine and 1,3-Azaborolyl-Anion Derivatives
Final Report Abstract
With this project, we developed a viable new pathway to dihydro-1,3-azaborinine derivatives by means of multicomponent reactions between the reagents FmesBH2 borane, acetylene and isonitrile. New 1,3-azaborole derivatives were identified and isolated as intermediates in these sequences. Aryl substituted 1,3-azaborole systems showed interesting photophysical properties, namely aggregation-induced emission (AIE) upon H2O addition to their THF solutions. Deprotonation of the 1,3-azaboroles gave the respective cyclopentadienide analogous anions which were used as η5-ligands in Organometallic Chemistry (Rh, Ir). Eventually, treatment of the 1,3-azaborole derivatives with various isonitriles CN-R (R: xylyl, benzyl, -CH2CO2tBu) gave the corresponding 1,3-azaborinine derivatives. Variations of these multicomponent routes gave dihydro-1,3- azaborinine derived oxindole isosteres. Replacement of the alkyne component by nitriles opened pathway to 1,4,2-diazaborole derivatives and we could also employ various olefins as reagents in the FmesBH2/isonitrile utilizing multicomponent B/N heterocycle syntheses. We also investigated some reactivity of the FmesBH2 reagent toward a phosphanyl substituted alkyne which opened a pathway to a geminal P/B frustrated Lewis pair. The results were described in detail in six original publications.
Publications
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Using the Secondary PH/BH Functional Groups of an Active Geminal Frustrated Lewis Pair for Carbon Monoxide Reduction and Reactions with Nitriles and Isonitriles. Angewandte Chemie International Edition, 59(30), 12477-12483.
Li, Jun; Mück‐Lichtenfeld, Christian; Daniliuc, Constantin G.; Kehr, Gerald & Erker, Gerhard
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Formation of amidino-borate derivatives by a multi-component reaction. Organic & Biomolecular Chemistry, 19(25), 5551-5554.
Li, Jun; Daniliuc, Constantin G.; Kehr, Gerald & Erker, Gerhard
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Introducing the Dihydro-1,3-azaboroles: Convenient Entry by a Three-Component Reaction, Synthetic and Photophysical Application. Journal of the American Chemical Society, 143(4), 2059-2067.
Li, Jun; Daniliuc, Constantin G.; Kartha, Kalathil K.; Fernández, Gustavo; Kehr, Gerald & Erker, Gerhard
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Multi-component synthesis of dihydro-1,3-azaborinine derived oxindole isosteres. Chemical Communications, 57(62), 7689-7692.
Li, Jun; Daniliuc, Constantin G.; Matern, Jonas; Fernández, Gustavo; Kehr, Gerald & Erker, Gerhard
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Three‐Component Reaction to 1,4,2‐Diazaborole‐Type Heteroarene Systems. Angewandte Chemie International Edition, 60(52), 27053-27061.
Li, Jun; Daniliuc, Constantin G.; Kehr, Gerald & Erker, Gerhard
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An olefin-based multi-component reaction to yield 1,2-azaborolidine derivatives. Dalton Transactions, 51(5), 1775-1778.
Li, Jun; Daniliuc, Constantin G.; Kehr, Gerald & Erker, Gerhard
