A PhI(OAc)2-promoted dioxygenation of allyl oximes, including one alkoxylation, has been developed. This reaction can give isoxazoline products bearing two contiguous tetrasubstituted carbons. Various oximes substrates bearing different aryl groups and tetrasubstituted-olefin moieties were compatible with the mild reaction conditions. A two-electron oxidation pathway was proposed based on results of
Friedel–Crafts-type cyclization. The reaction was catalyzed by a trimethylsilyl tricyanopalladate complex generated in situ from trimethylsilyl cyanide and Pd(OAc)2. Wide varieties of diethyl phosphates derivedfrom N-arylmandelamides were converted almost quantitatively into oxindoles. When N,N-dibenzylamide was used instead of an anilide substrate, a benzo-fused δ-lactam was obtained. An oxindole product was subjected
Tri-lacunary polyoxometalates of Na8H[PW9O34] as heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation and the synthesis of benzoxazole derivatives
作者:Shen Zhao、Yang Chen、Yu-Fei Song
DOI:10.1016/j.apcata.2014.01.017
日期:2014.4
development of tri-lacunary polyoxometalates (POMs) of Na8H[A-PW9O34]·7H2O and Na8H[B-PW9O34]·19H2O (Na-A-PW9 and Na-B-PW9) as highlyselective and efficient heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation of various aldehydes and ketones and the synthesis of benzoxazole derivatives at 25 °C under mild conditions. Since both Na-A-PW9 and Na-B-PW9 display no characteristic porosity
Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate
作者:Michael North、Marta Omedes-Pujol
DOI:10.3762/bjoc.6.119
日期:——
Propylene carbonate can be used as a green solvent for the asymmetricsynthesis of cyanohydrin trimethylsilyl ethers from aldehydes and trimethylsilyl cyanide catalysed by VO(salen)NCS, though reactions are slower in this solvent than the corresponding reactions carried out in dichloromethane. A mechanistic study has been undertaken, comparing the catalytic activity of VO(salen)NCS in propylene carbonate
The Zr(IV) metal–organicframework with 1,4-benzenedicarboxylate (UiO-66) in different forms was studied as a solid catalyst for carbonyl cyanosilylation. The anhydrous material (UiO-66-A) obtained after calcination has open Lewis-acid sites and acts as a heterogeneous and size selective catalyst for the reaction of aldehydes and trimethylsilylcyanide (TMSCN). Notably, it was found that the as-synthesized