Expedient Synthesis of Biginelli-Type Dihydropyrimidinones Using a-(Benzotriazolyl)alkyl Urea Derivatives A Novel Access to Disubstituted Acetylenes Expedient Acylations of Primary and Secondary Alkyl Cyanides to r-Substituted â-Ketonitriles Benzotriazole-mediated amidoalkylations of nitroalkanes, nitriles, alkynes and esters Aminoalkylation of nitriles by iminium ions generated in situ N-Sulfonylbenzotriazoles as Advantageous Reagents for C-Sulfonylation Efficient Conversion of Sulfones into â-Keto Sulfones by N-Acylbenzotriazoles§ Stereochemical aspects of novel 5,6-dihydro-4H-1,3-oxazines Amino(hetero)arylmethylation of Phenols with N-[r-Amino(hetero)arylmethyl]benzotriazoles Benzotriazole-Assisted Thioacylation