Synlett 1999; 1999(11): 1826-1828
DOI: 10.1055/s-1999-3171
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Concave Reagents 32: syn- and anti-Selective Cyclopropanation of Alkenes with Diazoacetates Catalyzed by Copper (i) Complexes of Concave 1,10-Phenanthrolines

Frank Löffler* , Martin Hagen, Ulrich Lüning
  • *Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany; Fax +49 (0) 4 31-8 80-15 58; E-mail:
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Publication History

Publication Date:
31 December 1999 (online)

Two classes of concave 1,10-phenanthroline ligands 1 and 2 have been used in the copper(i) catalyzed cyclopropanation of several acyclic and cyclic alkenes 3 with three diazoacetates 4-6. The bimacrocyclic 2,9-diaryl-1,10-phenanthrolines 1 favor the anti-(trans- or exo-) cyclopropanation with anti/syn-selectivities of up to >99 : 1 (8g). In contrast, with the 1,10-phenanthroline bridged calix[6]arenes 2 as ligands a rarely observed syn-selective cyclopropanation was achieved. Methyl diazoacetate (6) showed the best syn-selectivities with anti/syn-ratios of up to 14 : 86 (9g).