Aza‐Wittig Reaction in Natural Product Syntheses

Four-Component Preparation of Disubstituted 1,3,4-Oxadiazoles from (N-isocyanimino)triphenylphosphorane, Phenylacetylenecarboxylic Acid, Biacetyl and Primary Amines

“…16 It is expected (N-isocyanimino) triphenylphosphorane (4) to have synthetic potential because it develops a reaction system in which the iminophosphorane group can react with a reagent having a carbonyl functionality. 16,17 In recent years, we have confirmed a one-pot method for the preparation of organophosphorus compounds.…”

“…16 It is expected (N-isocyanimino) triphenylphosphorane (4) to have synthetic potential because it develops a reaction system in which the iminophosphorane group can react with a reagent having a carbonyl functionality. 16,17 In recent years, we have confirmed a one-pot method for the preparation of organophosphorus compounds. [18][19][20][21][22][23][24] As part of our ongoing program to develop efficient and robust methods for the preparation of heterocyclic compounds, [25][26][27][28][29][30][31][32][33][34][35][36][37][38] we wish to report the preparation of a new class disubstituted 1,3,4-oxadiazole derivatives 5a-j by a novel four-component condensation reaction of biacetyl (1), primary amine 2, (Nisocyanimino)triphenylphosphorane (4) and phenylacetylenecarboxylic acid (3) in excellent yields under neutral conditions (Scheme 1).…”

The Reaction of N-Isocyaniminotriphenylphosphorane with Cyclopentanone and A Primary Amine in the Presence of An E-Cinnamic Acid Derivative

“…These compounds are capable to be altered easily through the aza-Wittig reaction with carbon disulfide, isocyanates or carbon dioxide into functionalized heterocumulenes which display a wealthy chemistry of uncommon synthetic routes. 16 The nucleophilicity at the nitrogen is a factor of essential mechanistic importance in the use of these iminophosphoranes as aza-Wittig reagents. Iminophosphoranes are important reagents in synthetic organic chemistry, specially in the synthesis of naturally occurring products, compounds with biological and pharmacological activity.…”

Four-component Synthesis of 1,3,4-Oxadiazole Derivatives from (N-Isocyanimino)triphenylphosphorane, (E)-Cinnamic Acids, Acetaldehyde and Secondary Amines

“…The electron distribution around the P + -N − bond and its consequent chemical implications have been probed and assessed through theoretical, spectroscopic and crystallographic investigations [9]. The proton affinity of these iminophosphoranes can be 0932-0776 / 11 / 0200-0184 $ 06.00 c 2011 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com used as a molecular guide to assess their utility as synthetic reagents and their function as ligands in coordination and organometallic chemistry [9][10][11][12][13][14][15][16][17].…”

“…The nucleophilicity of the nitrogen atom is a factor of essential mechanistic importance in the use of these iminophosphoranes as aza-Wittig reagents. Iminophosphoranes are important reagents in synthetic organic chemistry, especially in the synthesis of naturally occurring products and of compounds with biological and pharmacological activity [9][10][11][12][13][14][15]. There are several reports for the use of (N-isocyanimino)triphenylphosphorane (4) in the preparation of metal complexes [16,17] (Scheme 1).…”