Vetiver oil is a highly esteemed basic ingredient of modern perfumery, but the nature of the constituents that really impart its typical and most sought woody-earthy scent has remained controversial. Indeed, vetiver oil is considered as one of the most complex essential oils, being mostly composed of several hundreds of sesquiterpene derivatives with a large structural diversity. Its complexity has hindered the direct identification of its odoriferous components. We thus aimed at using a combination of GC×GC/MS and GC-Olfactometry in order to identify most of its odor-impact constituents. The olfactory analysis of vetiver oil and vetiveryl acetate revealed a huge variety of odors in both products. While khusimone has almost unanimously been recognized as the most characteristic vetiver odorant, we have identified several even more important contributors to the typical vetiver character.

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A comprehensive and critical compilation of the volatile constituents of vetiver root (Chrysopogon zizanioides L.) is presented, including those present in its essential oil. This extremely complex material has stimulated analytical research for many decades in the hope of unravelling the secrets of its composition. Up to now, more than 300 molecules have been reported, mostly sesquiterpenoids possessing a large variety of skeletons, together with their norterpenic counterparts. This review attempts to clarify some of the discrepancies related to the characterization of these constituents, which were often due to the misuses of analytical methods without enough critical consideration of the literature. The identification of the main odour impact components of vetiver is also discussed, because much contradictory information appears in the literature on this subject. Copyright © 2014 John Wiley & Sons, Ltd.

Intramolecular hydroarylation of allenes was achieved under very mild conditions using bismuth(III) triflate as the catalyst. Efficient functionalization of activated and nonactivated aromatic nuclei led to C-C bond formation through a formal Ar-H activation. A tandem bis-hydroarylation of the allene moiety was also developed giving access to various interesting polycyclic structures.

The forthcoming extension of the regulated fragrance allergen number is raising a challenge: the previously developed quantification methods need to be drastically improved in terms of rapidity, without altering their reliability. This work describes a procedure based on comprehensive bidimensional gas chromatography, hyphenated with a low-cost quadrupole mass spectrometer (GCxGC-QMS). The second chromatographic dimension was operated in a dual configuration, consisting of two parallel secondary columns, one being connected to the QMS, the other to a flame ionization detector (FID). This not only allowed optimization of the chromatographic gas flows when compared to the usual single second dimension, but it also enabled the use of the FID signal to extend the quantification range from 2 to 10,000 mg/kg. The QMS was used at a low level (2-100 mg/kg), where coelutions are frequent, and the FID was used for the most abundant analytes (100-10,000 mg/kg) with a low risk of significant interferences. To assess the identity and purity of the analyte peak at low level, we propose a strategy and summarize it in a decisional tree. To our knowledge, this represents the first fully developed quantification method based on a GCx2GC-QMS/FID system. In contrast to other methods, it enables the quantification of a wide variety of analytes in fragrances in a single run, without requiring a series of sample dilutions to match the calibration range.KEYWORDS comprehensive bidimensional gas chromatography, fragrance allergens, mass spectrometry, parallel dual secondary column, quantification

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Bi(OTf) 3 -Catalyzed Cycloisomerization of Aryl-Allenes. -Cyclohydroarylation or tandem intramolecular cycloaddition reactions produce different types of polycycles. The reaction is mostly controlled by the temperature. Intermolecular tandem Friedel-Crafts allylation/alkylation reaction leads to a functionalized indan (XV). -(LEMIERE, G.; CACCIUTTOLO, B.; BELHASSEN, E.; DUNCAH*, E.; Org. Lett. 14 (2012) 11, 2750-2750, http://dx.doi.org/10.1021/ol3009667 ; Inst. Chim., Univ. Nice-Sophia-Antipolis, F-06108 Nice, Fr.; Eng.) -R. Steudel 40-028