Pier P. Piras
Pier P. Piras is a full professor of organic chemistry. He spent one year of postdoctoral work in 1980-1981 at the School of Physical and Molecular Sciences, University of Bangor-North Wales, under the guidance of Professor C. J. M. Stirling. He spent a sabbatical year in 1990-1991 at the Laboratoire des carbocycles of the University of Paris-sud (Orsay) working on cyclopropane derivatives with Professor Jacques Salaun. His present scientific interests are the synthesis and the use of strained carbocycles like cyclopropanes and cyclobutanes. He has studied particularly the reactivity of cyclopropanes in nucleophilic substitutions on transition metals (Pd, Mo) allylic complexes where he found that the synthesis of cyclopropylidene p-derivatives or alkenyl cyclopropanes is dependent on the soft or hard character of the nucleophile. The easy ring fission of cyclopropanes and cyclobutanes has been exploited for the synthesis of various heterocyclic derivatives. These syntheses are mainly based on the capture of the cyclobutyl thionium ion from electron rich aromatic compounds or from heteroatoms. Another one is based on the use of donor-acceptor cyclopropanes that allow an easy access to polysubstituted furans and pyrans. The aforementioned cyclopropanes and cyclobutanes have been also prepared in a chiral nonracemic form either using chiral auxiliaries or, more recently, using organocatalysts. Their ring expansion led in this way to new enantiomerically enriched carbo- and heterocyclic derivatives. Moreover, the use of cyclopropanes and cyclobutanes has allowed the total or formal synthesis of several natural derivatives in racemic or enantiomerically enriched form like muricatacin, (S)-cleonine, grandisol, calixolane B, alpha-cuparenone, herbertene, cuparene, and the alpha cuparene-1,4-quinone.
Biography Updated on 8 April 2012