Synthesis of Bis(2,4-diarylimidazol-5-yl) Diselenides from N-Benzylbenzimidoyl Isoselenocyanates
摘要:
The reaction of N-benzylbenzamides 6 with SOCl2 under reflux gave the corresponding N-benzylbenzimidoyl chlorides 7. Further treatment with KSeCN in dry acetone yielded imidoyl isosclenocyanates 3 (Scheme 2). These compounds, obtained in satisfying yields, proved to be stable enough to be purified and analyzed. Reaction of 3 with morpholine in dry acetone led to the corresponding selonourea derivatives 8. On treatment with Et3N, the 4-nitrobenzyl derivatives of type 3 were transformed into bis(2,4-diarylimidazol-5-yl) diselenides 9 (Scheme 3). This transformation takes place only when the benzyl residue bears an NO2 group and the phenyl group is not substituted with a strong electron-donating group. A reaction mechanism for the formation of 9 is proposed in Scheme 4. The key structures have been established by X-ray crystallography.
Pd-Catalyzed Thiocarbonylation with Stoichiometric Carbon Monoxide: Scope and Applications
摘要:
A general protocol for the Pd-catalyzed thiocarbonylation of aryl iodides with stoichiometric carbon monoxide has been established employing a catalytic system composed of Pd(OAc)(2) and DPEphos with low catalyst loading (1 mol %). Both electron-rich and -deficient aryl iodides proved effective for these couplings with aryl and alkyl thiols. The choice of the metal ligands and the solvent system was crucial for the efficiency and chemoselectivity of these transformations.
Pd-Catalyzed Thiocarbonylation with Stoichiometric Carbon Monoxide: Scope and Applications
作者:Mia N. Burhardt、Rolf H. Taaning、Troels Skrydstrup
DOI:10.1021/ol400138m
日期:2013.2.15
A general protocol for the Pd-catalyzed thiocarbonylation of aryl iodides with stoichiometric carbon monoxide has been established employing a catalytic system composed of Pd(OAc)(2) and DPEphos with low catalyst loading (1 mol %). Both electron-rich and -deficient aryl iodides proved effective for these couplings with aryl and alkyl thiols. The choice of the metal ligands and the solvent system was crucial for the efficiency and chemoselectivity of these transformations.
Synthesis of Bis(2,4-diarylimidazol-5-yl) Diselenides from N-Benzylbenzimidoyl Isoselenocyanates
作者:Plamen K. Atanassov、Yuehui Zhou、Anthony Linden、Heinz Heimgartner
The reaction of N-benzylbenzamides 6 with SOCl2 under reflux gave the corresponding N-benzylbenzimidoyl chlorides 7. Further treatment with KSeCN in dry acetone yielded imidoyl isosclenocyanates 3 (Scheme 2). These compounds, obtained in satisfying yields, proved to be stable enough to be purified and analyzed. Reaction of 3 with morpholine in dry acetone led to the corresponding selonourea derivatives 8. On treatment with Et3N, the 4-nitrobenzyl derivatives of type 3 were transformed into bis(2,4-diarylimidazol-5-yl) diselenides 9 (Scheme 3). This transformation takes place only when the benzyl residue bears an NO2 group and the phenyl group is not substituted with a strong electron-donating group. A reaction mechanism for the formation of 9 is proposed in Scheme 4. The key structures have been established by X-ray crystallography.