The (dl) a-keto esters 16, were prepared from the (dl) carbinols 1 to and from (dl) -2-hydroxyheptaElicene 5. These (dl) a-keto esters underwent NaBHq reductions to give the corresponding diastereomeric (dl) a-hydroxy esters 11, with 54 to -100% diastereaneric excesses.Highly enantioselective and/or diastereoselective syntheses are of great importance in organic chemistry. As an ultimate goal we aimed at the preparation and use o f chiral secondary alcohols and phenolewhich could lead to highly effective asymmetric inductions.process to evaluate the steric approach control as it is easy to modulate the bulkyness of the alkoxy moety of the ester '.available2'3 and proved to be efficient inducers in the reduction of the corresponding a-keto esters with NaBH4.The NaBH' reduction of a-keto esters was considered to be an efficient We have studied four secondary (dl) alcohols (1 to i) which are readily

SUMMARYAtrolactic syntheses have been carried out to evaluate the potentiality, in asymmetric syntheses, of chiral inducers. The (d1)-hydroxyhelicenes l, 2, the (dl) sec. alcohols 1-12 and the (d1)phenolic binaphtyl compound have been used as inducers. The d.e. are collected in table I (6-100%). The atrolactic asymmetric synthesis has also been carried out using three optically active inducers, namely : (-)-quinine 13, (-)-l0,ll-dihydroquinine -14, and R(-)-2,2,2-trifluoro-1-(9-anthryl)ethanol 5. Diastereomeric and enantiomeric excesses equal or greater than 88% have been obtained in six cases out of sixteen :(l-naphtyl)-(9-anthryl)methanol 3 (d.e = 90%) ; 2,2,2-trichloro-1-(9-anthryl) ethanol 7 (d.e = 100% ?2), 2,2,2-tribromo-1-(9-anthryl)ethanol 8 (d.e = 100% +2), (-)=quinine 13 (e.e = 95.5%), and (-)-2,2,2-trifluoro-l-(9-anthryl) ethanol 6 (e.e = 88%).

Enantioselective hydrogenation using chiral complexes between atropisomeric diphosphines and ruthenium is a powerful tool for producing chiral compounds. Using a simple and straightforward in situ catalyst preparation, the conditions were optimized using molecular hydrogen for both academic and industrial purposes. This led to the best conditions and the lowest catalytic ratio required for the pressure used. Hydrogenation of various b-keto esters was efficiently performed at atmospheric and higher pressures, leading to the use of very low catalystsubstrate ratios up to 1/20,000. Asymmetric hydrogenations were used in key-steps towards the total synthesis of corynomycolic acid, Duloxetine and Fluoxetine.

Helical arrangements and the associated chirality have wellknown implications in a variety of areas ranging from natural biological systems to materials science. In particular orthofused polyaromatic systems with p-conjugated helical structures display unique physicochemical properties which have stimulated countless studies [1] oriented towards self-assembly and chiral recognition, [2] chiroptical devices, [3] molecular machines, [4] material chemistry, [5] organometallic and organocatalysis, [6, 7] as well as asymmetric synthesis. [8, 9] In the general context of the growing interest in helical derivatives, helicenes displaying phosphorus functions represent promising scaffolds. Trivalent phosphorus functions and the related metal complexes are easily designed to tune the electronic and physicochemical properties of helicenes, [10] as well as to offer a wide range of potential uses in organometallic chemistry and catalysis. It is therefore rather surprising to note that the field today is still in its infancy, first of all in terms of number of compounds as well as structural diversity. So far, most phosphorus derivatives having helical chirality display polyaromatic (or heteroaromatic) helical scaffolds with pendant phosphorus functions (phosphites, [2a, 6b, 11] trivalent phosphines and phosphine oxides, [6a, 12] phospholes, [10a,b] etc.). Very little is known about their properties and behaviors.The aim of this work is to expand the range of heterohelicenes to chiral helicenes where phosphorus is embedded within the helical framework itself, at the external edge of the fused ring sequence (Figure 1). Helical phosphines of this class would not only display peculiar electronic features resulting from extended p conjugation, but also take full advantage of the dissymmetric steric environment generated by the helical chirality at the external edge. Helicenes of this class are unknown to date, whereas phosphahelicenes, wherein phosphorus is embedded in the internal section of the helical framework, have been reported only recently by Tanaka and co-workers and Nozaki and co-workers. [13] We intend to disclose here: a) the first diastereo-and enantioselective access to [6]-and [7]helicenes in which the fused ring sequence ends with a phosphole unit; b) the structural and chiroptical properties of enantiomerically pure derivatives of this class; c) the enantiospecific self-assembly of columnar arrangements in the solid state; and d) the photochemical [2+2] annulations of phosphole-fused [6]helicenes into dimeric helical structures.When targeting helicenes where phosphorus is embedded within the helical framework itself, we envisioned 1Hphosphindole oxides as suitable building blocks and have adapted the classical helicene synthesis, based on the photochemical cyclization/dehydrogenation of diarylolefins, to these substrates. [14] Our starting materials are the olefins 5 which combine a 1H-phosphindole unit and a benzo[c]phenanthrene fragment. They have been prepared according to a known procedure, [15] by usi...

The yield and composition variation of the leaf essential oil from Myrtus communis L, an aromatic wild plant which grows in the area of Tabarka (north-western Tunisia) were investigated. Essential oil was obtained by steam distillation at atmospheric pressure of the dried, ground herbal material. The yield of essential oil reached a peak at the beginning of the flowering stage (0.54%) and a minimum after the flowering period (0.27%). Thirty-nine components were identified in the essential oil by GC and GC-MS. The major constituent of the oil was found to be a-pinene. Copyright

Dedie a la memoire de Nicole Defay, Dr. Sc.

Herein, we report the Pd-catalyzed regioselective direct arylation of heteroarenes in which benzenesulfonyl chlorides are used as coupling partners through a desulfitative cross-coupling that can be performed in diethyl carbonate (DEC) or cyclopentyl methyl ether (CPME) as green and renewable solvents or even in neat conditions instead of dioxane or dimethylacetamide (DMA). Under these solvent conditions, the reaction proceeds with a wide range of heteroarenes. C2- or C5-arylated products were obtained with furan and pyrrole derivatives. Benzofuran was also arylated regioselectively at the C2-position, whereas the reaction proceeds selectively at the C3- or C4-positions if thiophenes and benzothiophenes are used. Moreover, in some cases, especially with 1-methylindole, solvent-free conditions afforded better regioselectivities and/or yields than the reaction performed in the presence of solvents.

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