Gonell Sergio, Reek Joost N H
Homogeneous, Supramolecular and Bio-Inspired Catalysis, Van't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 Amsterdam 1098XH The Netherlands.
Current address: Department of Chemistry University of North Carolina at Chapel Hill Chapel Hill, North Carolina 27599-3290 USA.
ChemCatChem. 2019 Mar 6;11(5):1458-1464. doi: 10.1002/cctc.201900089. Epub 2019 Feb 11.
Gold-catalyzed cycloisomerization reactions have been explored using guanidinium functionalized ML nanospheres that strongly encapsulate gold complexes functionalized with a sulfonate group through hydrogen bonds. As the ML nanospheres can bind up to 24 gold complexes, the effect of local catalyst concentration on the reaction outcome can be easily evaluated. Also, the guanidinium groups of the sphere can weakly interact with the carboxylic group of the substrates, facilitating the pre-organization of the substrate near to the catalytic active site. Both effects can influence the selectivity and rate of the gold-catalyzed transformation. Challenging acetate-containing substrates with internal acetylene functional groups can be cyclized efficiently within the ML nanospheres, where the pre-organization of the substrate plays a crucial role. For 2-alkynyl benzoic acids the selectivity of the reaction can be controlled by adjusting the local concentration of gold catalyst in the guanidinium functionalized ML nanosphere.
人们利用胍基功能化的ML纳米球探索了金催化的环异构化反应，该纳米球通过氢键强烈包裹用磺酸酯基团功能化的金配合物。由于ML纳米球最多可结合24个金配合物，因此可以轻松评估局部催化剂浓度对反应结果的影响。此外，纳米球的胍基可与底物的羧基发生弱相互作用，促进底物在催化活性位点附近的预组织。这两种效应均可影响金催化转化的选择性和速率。具有内部乙炔官能团的具有挑战性的含乙酸酯底物可在ML纳米球内高效环化，其中底物的预组织起着关键作用。对于2-炔基苯甲酸，可通过调节胍基功能化ML纳米球中金催化剂的局部浓度来控制反应的选择性。
