The synthesis of the 2,3-bisphosphite derivatives of phenyl 4,6-O-benzylidene-beta-D-glucopyranoside leads to new chelating ligands. Their rhodium(I) and platinum(II) complexes have been tested as catalysts for the asymmetric hydroformylation of vinyl acetate, allyl acetate and p-methoxystyrene. Good regioselectivity (>90% branched product), but an enantioselectivity of only less than or equal to 36% ee were found under mild reaction conditions (25-40 degrees C, 40-70 bar syngas). (C) 1998 Elsevier Science Ltd. All rights reserved.
The synthesis of the 2,3-bisphosphite derivatives of phenyl 4,6-O-benzylidene-beta-D-glucopyranoside leads to new chelating ligands. Their rhodium(I) and platinum(II) complexes have been tested as catalysts for the asymmetric hydroformylation of vinyl acetate, allyl acetate and p-methoxystyrene. Good regioselectivity (>90% branched product), but an enantioselectivity of only less than or equal to 36% ee were found under mild reaction conditions (25-40 degrees C, 40-70 bar syngas). (C) 1998 Elsevier Science Ltd. All rights reserved.
Ammonium Salt-Catalyzed Highly Practical <i>Ortho</i>-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
作者:Xiaodong Xiong、Ying-Yeung Yeung
DOI:10.1021/acscatal.8b00327
日期:2018.5.4
An ortho-selective ammonium chloride salt-catalyzed direct C–H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated
Synthetic Approaches to Zigzag-Shaped Oligophenylene Strands Laterally Decorated with Hydroxy Functions
作者:Carine Diebold、David Michael Weekes、Maria Torres Navarrete、Pierre Mobian、Nathalie Kyritsakas、Marc Henry
DOI:10.1002/ejoc.201001058
日期:2010.12
Two nanosized zigzag-shapedoligophenylenestrands incorporating 2,2′-biphenol units were prepared by Suzuki–Miyaura coupling methodology. The two strands are made up of ten and seven phenyl rings, respectively. Two synthetic pathways were evaluated. The first involved the preparation of the target oligophenylene molecules by a sequential approach, whereas the second entailed the formation of the precursors