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N,N‐Dimethylaminobenzotriazolylcarbene (5) reacted with phenyl isocyanate in a [1+2+2] cycloaddition and then with nucleophiles to generate various hydantoins 10 in a one‐pot procedure. It was also found that this novel carbene reacted with trans‐dibenzoylethylene (11) in a [1+4] cycloaddition, generating 2‐dimethylamino‐3‐benzoyl‐5‐phenylfuran (13) and 2‐phenyl‐3‐[benzotriazol‐1‐yl]‐4‐benzoylfuran (14) whose structures were confirmed by 1H‐13C long range correlations as well as the structure of furan 14 being confirmed by X‐ray crystallography.

Lithiation with n-butyllithium of a variety of benzotriazole derivatives 1a − f and 5a − d, all containing a proton α to the benzotriazolyl moiety, gave anions which underwent addition to aliphatic, aromatic, and α,β-unsaturated aldehydes and cyclic and acyclic ketones. The resultant N-(β-hydroxyalkyl)benzotriazole derivatives 3a − m, 6a − g, 9a − d, and 10a were dehydroxybenzotriazolylated when treated with low-valent titanium to give alkenes 4a − m, dienes 7a − j, and triene 11a, with selectivity for the trans isomers without separation of diastereoisomeric intermediates. This method offers an alternative to the three most frequently used methods for the formation of alkenes from carbonyl compoundsthe Wittig, Peterson, and Julia reactionsespecially in the formation of tri- and tetrasubstituted alkenes.

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Generation and Reactivity of N,N-Dimethylaminobenzotriazolylcarbene a New Nucleophilic Carbene.-The title carbene (V), generated by deprotonation of salt (III) under mild conditions, affords dimeric products (VI) and (VII). It reacts with Ph-NCO (VIII) and various nucleophiles like H2O and (XII) to give the corresponding hydantoins, e.g. (X) and (XIII), via (1 + 2 + 2) cycloaddition in a one-pot procedure. (1 + 4) cycloaddition of carbene (V) with reactant (XIV) provides furans (XV) and (XVI). The structure of product (XV) is confirmed by X-ray analysis.-(KATRITZKY, A. R.; CHENG, D.; LEEMING, P.; GHIVIRIGA, I.; HARTSHORN, C. M.; STEEL, P. J.; J.

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Trans-Selective Olefination of Carbonyl Compounds by Low-ValentTitanium-Mediated Dehydroxybenzotriazolylation.-A convenient and stereocontrolled olefination of aldehydes and ketones is developed by reacting the carbonyl compounds with lithiated benzotriazole derivatives followed by low-valent titanium (LVT) mediated dehydroxybenzotriazolylation. This method offers good stereoselectivity without any need to isolate diastereomeric intermediates and complements the Wittig, Peterson and Julia reactions. A variety of methods for the generation of the LVT reagent is also investigated, starting either from TiCl 3 or from TiCl 4 , which is more readily available from commercial sources. -(KATRITZKY, A. R.; CHENG, D.; HENDERSON, S. A.; LI, J.; J.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.