A number of aliphatic and arylaliphatic a,b-epoxy ketones were prepared in good yields in a one-pot procedure by a manganese-catalyzed ring cleavage of 1-substituted and 1,2disubstituted cyclopropanols with oxygen followed by dehydration of the resulting cyclic peroxides with alkali.

The stereochemistry of the Kulinkovich cyclopropanation of nitriles with alkenes has been examined by employing (E)-disubstituted alkenes and deuterium-labeled homoallylic alcohols as a stereochemical probe. An intramolecular cyclopropanation proceeds with preservation of the olefin configuration. On the other hand, intermolecular counterparts occur with both preservation and reversal of the olefin configuration, which corresponds to retention and inversion of configuration at the Ti–C bond, respectively, in the cyclopropane-forming step. These uncommon stereochemical outcomes contrast with that of the Kulinkovich cyclopropanation of tertiary amides.

No abstract

The Kulinkovich cyclopropanation of esters with disubstituted homoallylic alcohols is described for the preparation of 1,2,3‐trisubstituted cyclopropanols. Central to the successful implementation is the generation in situ of a temporary alkoxy tether between a homoallylic alcohol and an alkoxytitanium species to override unfavorable steric factors.

No abstract