Synthesis of new chiral pincer-complex catalysts for asymmetric allylation of sulfonimines |
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Authors: | Olov A Wallner Lars Eriksson |
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Institution: | a Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden b Department of Inorganic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden |
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Abstract: | Four new chiral pincer-complexes were prepared based on coupling of BINOL and TADDOL moieties with iodoresorcinol followed by oxidative addition of palladium(0). The X-ray analysis of complex 5a revealed that the BINOL rings form a well-defined chiral pocket around the palladium atom. This chiral environment can be further modified by γ-substitution of the BINOL rings. Preliminary studies for electrophilic allylation of sulfonimine 2 with allylstannane revealed that the presented chiral complexes are promising asymmetric catalysts for preparation of chiral homoallyl amines. The best result was achieved employing catalytic amounts of γ-Me BINOL complex 6 affording homoallyl amine 4 with 59% ee and 74% isolated yield. |
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Keywords: | Pincer-complexes Homogenous catalysis Palladium Allylation Chiral catalyst |
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