Paolo Ceccherelli

β-Keto esters from the rhodium(II) acetate catalysed conversion of α-diazo-β-hydroxy esters

A new and efficient procedure for the transformation of α-diazo-β-hydroxy esters into the corresponding β-keto esters, which involves the use of Rh2(OAc)4, is described.

Sesquiterpene acids from Dittrichia viscosa

Abstract Dittrichia viscosa afforded in addition to compounds reported previously, ilicic acid and two new sesquiterpene acids. The structures of the new compounds were established by chemical and spectral methods.

OXONE PROMOTED NEF REACTION. SIMPLE CONVERSION OF NITRO GROUP INTO CARBONYL

Abstract A mild and convenient oxidative Nef reaction using Oxone® (potassium hydrogen persulfate) is described. Following our procedure primary and secondary nitroalkanes generate carboxylic acids and ketones, respectively, both in good yields. †Deceased on January 1st 1998

ONE-STEP CONVERSION OF OXIMES TO GEM-CHLORO-NITRO DERIVATIVES

Abstract a new method for one-pot conversion of oximes to gem -chloro-nitro compounds using Oxone and sodium chloride is described.

Isolation and structure of a quassinoid from Ailanthus glandulosa

Abstract A new quassinoid, 2-dihydroailanthone, has been isolated from the bark of Ailanthus glandulosa . Its structure was established on the basis of spectroscopic data and chemical evidence.

Biogenetic-type transformation of 3-keto-4,5-epoxy-eudesmanes: synthesis of cyperanes, eremophilanes and spirovetivanes

Abstract Cyperanes, eremophilanes and spirovetivanes have been prepared by acid catalyzed rearrangement of 3-keto-4,5-epoxy-eudesmanes. These transformations are of biogenetic significance and reinforce thehypothesis that the oxigenate eudesmanes are precursors of severalsesquiterpene skeletons.

Rh2(OAc)4-mediated decomposition of diazocarbonyl compounds: A comparison of α-diazo ketones and α-diazo β-keto esters reactivity.

Abstract Unsaturated α-diazocarbonyl compounds undergo intramolecular cyclopropanation or carbon-hydrogen bond insertion when catalyzed by Rh2(OAc)4: α-diazo ketones react preferentially with carbon-carbon doubled bond, whereas closely related α-diazo-β-keto-esters insert into carbon-hydrogen bond.

Trans 1,2-functionalization of cycloalkenes using selenium intermediates

Abstract The reaction of excess phenylselenenyl halides with trisubstituted cyclic olefins in aqueous acetonitrile is regio- and stereospecific and affords trans halohydrins in excellent yields. The reaction proceeds through the formation of a β-hydroxyalkyl phenyl selenide which evolves to halohydrin presumably via an epoxy-intermediate.

Brominative lactonization in eudesmanes.

Abstract The interaction of ilicic acid 1 with bromine affords directly the bromolactone 3 .

Selenoxides as leaving groups: Synthesis of epoxides

Abstract β-Hydroxyselenoxides, prepared from substituted cyclohexenes, have been selectively transformed into chiral epoxides by treatment with alkali.