Synfacts 2007(10): 1030-1030  
DOI: 10.1055/s-2007-968975
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Ru- and Mo-Catalyzed Asymmetric Synthesis of Pyrans and Piperidines

Contributor(s): Victor Snieckus, Katie Groom
G. A. Cortez, C. A. Baxter, R. R. Schrock, A. H. Hoveyda*
Boston College, Chestnut Hill and Massachusetts Institute of Technology, Cambridge, USA
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Publikationsverlauf

Publikationsdatum:
07. November 2007 (online)

Significance

Reported is a detailed comparison of one Mo- and four Ru-based chiral catalysts (E, and A-D, respectively) in asymmetric ring-opening/cross-metathesis (AROM/CM) reactions of oxa- and azabicycles, resulting in chiral functionalized pyrans and piperidines. Compared to the Ru-complexes, the more active Mo-complex E is the most effective desymmetrization catalyst with less reactive substrates (e.g. 3b). With more reactive 3a, oligomeric products were obtained. In contrast, the less reactive Ru-catalysts perform efficient desymmetrizations with both 4a and 4b. Although the reaction is more sluggish with 4b, higher enantioselectivity is obtained than with the Mo-catalyst.