Stabilized phosphorus ylides, versatile intermediates in synthetic organic chemistry can be prepared by the novel reaction of dialkyl acetylenedicarboxylates (DAAD), triphenylphosphine (TPP) and acids such as phenols, imides, amides, enols, oximes and alcohols. The reaction involves an intermediate formed by the 1:1 conjugate addition reaction of the TPP to DAAD and concomitant protonation of the intermediate by an acid leads to vinyltriphenylphosphonium salts. The salts are unstable intermediates and converted to stabilized phosphorus ylides via Michael addition reaction. The stabilized phosphorus ylides are able to take part in the normal intramolecular Wittig reactions but they are not generally able to participate in the normal intermolecular Wittig reactions. The intermolecular Wittig reactions of the ylides are observed only with highly electron-poor carbonyl groups such as indane-1,2,3-trione. The ylides are converted to electron-poor alkenes via elimination of TPP in solvent-free conditions. Almost all of the final products are valuable families of compounds. †Dedicated to Professor Issa Yavari on the occasion of his 59th birthday.

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A new method for preparing 1,2,3-triazols via a [3+2]-cycloaddition reaction is introduced. The effect of reaction temperature on the epoxide ring opening reactions is also investigated.

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. This manuscript has been accepted after peer review and appears as an Accepted Article online prior to editing, proofing, and formal publication of the final Version of Record (VoR). This work is currently citable by using the Digital Object Identifier (DOI) given below. The VoR will be published online in Early View as soon as possible and may be different to this Accepted Article as a result of editing. Readers should obtain the VoR from the journal website shown below when it is published to ensure accuracy of information. The authors are responsible for the content of this Accepted Article. FULL PAPER Electronic effects of aromatic rings on the catalytic activity of dioxidomolybdenum(VI)-hydrazone complexesRahman Bikas, [a,*] Vito Lippolis, [b,*] Nader Noshiranzadeh, [a] Hossein Farzaneh-Bonab, [a] Alexander J. Blake, [c] Milosz Siczek, [d] Hassan Hosseini-Monfared, [a] and Tadeusz Lis [d] Abstract:Nine dioxidomolybdenum(VI) complexes were synthesized by the reaction of MoO3 with tridentate hydrazone Schiff base ligands obtained from the reaction of aromatic acid hydrazides (3-hydroxy-2-naphthoic acid hydrazide, 4-pyridine carboxylic acid hydrazide or 2-furane carboxylic acid hydrazide) and ortho-hydroxy aldehyde derivatives (5-iodo-2-hydroxybenzaldehyde, 2-hydroxy-1-naphthaldehyde or 2-hydroxy-3-methoxybenzaldehyde). All ligands and complexes were characterized by elemental analysis and spectroscopic methods. The structures of seven complexes were further elucidated by single-crystal X-ray diffraction analysis which indicated a distorted octahedral geometry at the metal centre. Spectroscopic and X-ray analyses indicated that the ligands are coordinated to the molybdenum(VI) ion as dinegative ligands due to deprotonation of phenolic OH and amidic NH groups upon complexation. These complexes were used as catalyst in the oxidation of cyclooctene and thioanisole in the presence of hydrogen peroxide as environmental friendly oxidant. In order to achieve the highest catalytic activity, the effects of important parameters such as solvent, temperature and the molar ratio of oxidant to substrate were optimized. The results indicate that electron-withdrawing substituents on the ligands increase the catalytic activity of dioxidomolybdenum(VI)-hydrazone complexes.

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