- Evidence for Halogen Bonding in Amorphous Solid Dispersions
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Carbon-bound halogen atoms (iodine, bromine, chlorine, and occasionally fluorine) are known to act as electron acceptors and form interactions with different species capable of acting as electron donors. This interaction is termed halogen bonding and shar
- Deac, Alexandru,Gao, Yi,Indulkar, Anura S.,Mo, Huaping,Qi, Qingqing,Que, Chailu,Taylor, Lynne S.,Zeller, Matthias,Zemlyanov, Dmitry Y.,Zhang, Geoff G. Z.
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p. 3224 - 3235
(2020/05/27)
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- Benzoxaborole Catalyst for Site-Selective Modification of Polyols
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The site-selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site-selective and protecting-group-free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a–k were synthesized. In-depth analysis for the substituent effect revealed that 1i–k, bearing multiple electron-withdrawing fluoro- and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i-catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis-1,2-diol derivatives proceeded with good yield and site-selective manner.
- Kusano, Shuhei,Miyamoto, Shoto,Matsuoka, Aki,Yamada, Yuji,Ishikawa, Ryuta,Hayashida, Osamu
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supporting information
p. 1598 - 1602
(2020/02/11)
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- Synthesis, Coordination Properties, and Catalytic Application of Triarylmethane-Monophosphines
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A new class of triarylmethane-based phosphines (L1-L4) and their Pd(II) and Rh(I) complexes were synthesized and subsequently characterized by NMR spectroscopy and X-ray diffraction analysis. The reactions of these phosphines with [PdCl(π-allyl)]2 gave the square-planar Pd(II) complexes [PdCl(π-allyl)(L)] (L = L1-L4). The treatment of [PdCl(π-allyl)(L3)] and [PdCl(π-allyl)(L4)], which have CF3-substituted triarylmethane and 9-arylfluorene moieties, respectively, with LiOtBu afforded P,C(sp3)-chelated palladacycle complexes. Reversibility between a C(sp3)-M covalent bond and a C(sp3)-H···M interaction was experimentally demonstrated using [RhCl(nbd)]2 as a Rh(I) source. The triarylmethane-monophosphines L1-L4 were applied to the Pd-catalyzed 1,4-addition of arylboronic acids to enones.
- Iwai, Tomohiro,Tanaka, Ryotaro,Sawamura, Masaya
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p. 3959 - 3969
(2016/12/22)
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- Substitution controlled functionalization of ortho -bromobenzylic alcohols via palladium catalysis: Synthesis of chromenes and indenols
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An efficient domino Pd-catalyzed transformation of simple ortho-bromobenzyl tertiary alcohols to chromenes is presented. Their formation is believed to proceed via the formation of a five-membered palladacycle, which, in turn, involves in an intermolecular homocoupling with the second ortho- bromobenzyltertiary alcohol to yield the homo-biaryl bond followed by intramolecular C-O bond formation. Interestingly, when there is an allylic substituent on the benzylic carbon atom, a chemoselective switch was observed, which preferred intramolecular Heck coupling and gave indenols. Further, it has been confirmed that the tertiary alcohol functionality is indispensible to give the coupled products, whereas the use of primary/secondary benzylic alcohols furnished the simple carbonyl products via a possible reductive debromination followed by oxidation due to the availability of β-hydrogen(s).
- Mahendar, Lodi,Satyanarayana, Gedu
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supporting information
p. 2059 - 2074
(2014/04/03)
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- Chiral allene-containing phosphines in asymmetric catalysis
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We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic ac
- Cai, Feng,Pu, Xiaotao,Qi, Xiangbing,Lynch, Vincent,Radha, Akella,Ready, Joseph M.
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supporting information; experimental part
p. 18066 - 18069
(2012/01/04)
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