Aromatic glyoxalimines in criss-cross cycloaddition reactions

One-Step Redox Route to N-Heterocyclic Phosphenium Ions

“…All solvents were distilled over sodium benzophenone ketyl, except dichloromethane, which was distilled over CaH 2 and degassed prior to use. The α-diimines RNC(H)C(H)NR [R = t -Bu, Mes, 2,6- i -Pr 2 C 6 H 3 , Cy, and ( p -tol)NC(Me)C(Me( p -tol))] were prepared according to the literature procedures. Phosphorus triiodide and Na[B(C 6 H 5 ) 4 ] were obtained from commercial sources and used without further purification.…”

The Criss‐Cross Cycloaddition: A Simple Access to Valuable Heterocycles and Polymers

“…[39e] In the cases of unsymmetrically substituted alkynes, a regioselectivity was noticed by the authors -the best was observed with alkyne 171 c and low with 171 b Scheme 24. From their studies, they isolated only single stereoisomer with symmetrical alkynes whileas with unsymmetrical alkynes both the regioisomers were formed -the ratio was confirmed by 1 H-and 19 F-NMR spectroscopy. On the other hand, the regioselectivity slightly increases from electron-releasing to the electron-withdrawing substitution on the phenyl ring.…”

“…ChemistrySelect rangement as a key step, and in order to evade the realization of the symmetrical azine one of the nitrogen of the hydrazine monohydrate was blocked by creation of diethyl hydrazidophosphate. [39c,d] The CCC reaction was performed in dry refluxing xylene: the desired products were formed via an intermediate 165, and the progression of the reaction was monitored by means of 19 F-NMR spectroscopy. The formation of thus prepared compounds was further anticipated from quantum chemistry calculations.…”

“…Interestingly, from the X-ray analysis, they were able to decide the configurations at the chiral centres of thus prepared products. Finally, the structures of the CCC products 172 a-g were established by means of GC-MS, IR, 1 H, 13 C, and 19 F-NMR besides the DEPT-135 spectral data. Additionally, the interactions between protons and carbons were consigned using 2D-NMR such as COSY, HMBC and HMQC, and the molecular weights were investigated by means of GC-MS -to identify their corresponding molecular ion-peaks.…”

“…Moreover, they have also prepared the compounds 21 and 22 through same method Scheme 5. To further extent this methodology, they have also prepared perhydroimidazo[4,5‐d]imidazole‐2,5‐dithiones 24 and 25 Scheme 5 [19] . To this regard, when the reaction was performed with potassium thiocyanate/AcOH, the products ( 24) obtained from this reaction were in decent yields.…”