Reported here is the Pd-catalyzed C-N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as lowas100 ppm of Pd and KOHa sb ase.M echanistic studies revealed two catalyst resting states:a na rylpalladium(II) hydroxidea nd arylpalladium(II) chloride.T hese compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate-limiting deprotonation of ah ydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium-(II) hydrazido complex.

No abstract

Reported here is the Pd-catalyzed C-N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as lowas100 ppm of Pd and KOHa sb ase.M echanistic studies revealed two catalyst resting states:a na rylpalladium(II) hydroxidea nd arylpalladium(II) chloride.T hese compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate-limiting deprotonation of ah ydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium-(II) hydrazido complex.

No abstract

Benzofuran derivatives R 0070Synthesis of Novel Oxygen Heterocycles: 1,10-Dioxa-cyclopenta[a]fluorene and Benzo[b]naphtho[2,1-d]furans via Doetz Intramolecular Benzannulation. -A synthesis of alkyne-tethered aryloxy chromium Fischer carbene complexes (III) and (VI) is developed. Their successful thermal intramolecular Doetz benzannulation affords titled compounds (IV) and (VII). -(SEN*, S.; KULKARNI, P.; BORATE, K.; PAI, N. R.; Tetrahedron Lett. 50 (2009) 28, 4128-4131; Res. Dev.,