Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.
Institute of Materials Research and Engineering, A*STAR, 2 Fusionopolis Way, Singapore, 138634, Singapore.
Angew Chem Int Ed Engl. 2016 Jun 1;55(23):6739-43. doi: 10.1002/anie.201601709. Epub 2016 Apr 21.
The asymmetric arylation of 2,2-dialkyl cyclopent-4-ene-1,3-diones with aryl boronic acids was found to be efficiently catalyzed by a chiral diene-rhodium μ-chloro dimer, [{RhCl((R)-diene*)}2 ], in the absence of bases in toluene/H2 O to give 2,2-dialkyl 4-aryl cyclopentane-1,3-diones in high yields with high enantioselectivity. Such compounds can not be obtained with high enantiomeric purity under the standard basic conditions used for rhodium-catalyzed asymmetric arylation because the α-aryl ketone products undergo racemization under the basic conditions.
2,2-二烷基环戊-4-烯-1,3-二酮与芳基硼酸的不对称芳基化反应被发现可以在没有碱的甲苯/H2O 中高效地被手性二烯-铑 μ-氯二聚体 [{RhCl((R)-diene*)}2] 催化，以高收率和高对映选择性得到 2,2-二烷基 4-芳基环戊烷-1,3-二酮。在铑催化的不对称芳基化反应中使用的标准碱性条件下，这些化合物无法获得高对映体纯度，因为在碱性条件下α-芳基酮产物会发生外消旋化。
