Marc Nicolas

On the elucidation of the mechanism of Vinca alkaloid fluorination in superacidic medium.

Detailed investigations on one of the key steps of the superacidic fluorination of Vinca alkaloids that is the origin of C20 activation are reported. While two different pathways can be envisioned for the emergence of the transient secondary carbocationic intermediate, isotopic labeling experiments unambiguously revealed the involvement of a 1,2-hydride shift mechanism.

Semisynthesis of Macrocarpal C and Analogues by Selective Dehydration of Macrocarpal A or B

Macrocarpals A and C are structurally related compounds that have been extracted from different Eucalyptus species. Although macrocarpal C is of biological interest, its isolation in pure form is difficult to achieve. We report herein an efficient method for the semisynthesis of macrocarpal C by selective exo-dehydration of another member of the macrocarpal family, macrocarpal A. We also report the semisynthesis of three new macrocarpal structures derived from either macrocarpal A or B.

Asymmetric Synthesis of (+)-Mequitazine from Quinine

The first asymmetric synthesis of the antihistaminic drug mequitazine is reported. Our approach started from quinine, a Cinchona alkaloid, whose chiral information was exploited for setting up the stereogenic center of (+)-mequitazine.

Enantioselective synthesis of a cyclobutane analogue of Milnacipran

The asymmetric synthesis of a cyclobutane analogue of the antidepressant drug Milnacipran is reported. The optically active derivative incorporates a central cyclobutane ring in lieu of the cyclopropane unit classically found in Milnacipran. The two stereogenic centres borne by the cyclobutane were sequentially installed starting from phenylacetonitrile.