Pinacol coupling of benzaldehydes mediated by titanium complexes displaying amine bis(phenolate) ligands
作者： Sónia Barroso , Pedro Adão , Ana M. Coelho , João Costa Pessoa , Ana M. Martins
DOI: 10.1016/J.MOLCATA.2015.11.021
关键词:
摘要: Abstract Titanium amine bis(phenolate) complexes of general formulas [Ti(L)Cl(THF)], [Ti(L)X 2 ] and [{Ti(L)Cl} -μ-O] (X = Cl, O i Pr) were assessed as catalysts PhCHO pinacol coupling. In optimal conditions (7.5 mol% catalyst load, 55 °C 16 h reaction time in THF) TMSCl additive, [Ti(L3)Cl ( 11 ) is the most efficient giving 100% conversion 95% yield diol with a ratio DL : meso = 57:43 27% ee . Using acidic additives, lower yields but higher diasteriomeric ratios are obtained. No significant improvements observed when p -substituted benzaldehydes used. The reduction Ti(IV) to Ti(III) species identified by EPR stoichiometric between [Ti III (L1)Cl(THF)] 6 benzaldehyde shows that coupling occurs 72%. Different D,L obtained absence or presence reducing metals indicate different may form, namely mono- trinuclear species.
sci-hub.se 参考文章(30)
Pedro Adão, João Costa Pessoa, Rui T. Henriques, Maxim L. Kuznetsov, Fernando Avecilla, Mannar R. Maurya, Umesh Kumar, Isabel Correia, Synthesis, characterization, and application of vanadium-salan complexes in oxygen transfer reactions. Inorganic Chemistry. ,vol. 48, pp. 3542- 3561 ,(2009) , 10.1021/IC8017985
Jiwu Wen, Jun Zhao, Tianpa You, Asymmetric pinacol coupling catalyzed by TADDOL-titanium complexes Journal of Molecular Catalysis A-chemical. ,vol. 245, pp. 278- 280 ,(2006) , 10.1016/J.MOLCATA.2005.09.042
Pedro Adão, Sónia Barroso, Fernando Avecilla, M. Conceição Oliveira, João Costa Pessoa, CuII–salan compounds: Synthesis, characterization and evaluation of their potential as oxidation catalysts Journal of Organometallic Chemistry. ,vol. 760, pp. 212- 223 ,(2014) , 10.1016/J.JORGANCHEM.2013.10.019
Edit Y Tshuva, Miriam Versano, Israel Goldberg, Moshe Kol, Hana Weitman, Zeev Goldschmidt, Titanium complexes of chelating dianionic amine bis(phenolate) ligands: an extra donor makes a big difference Inorganic Chemistry Communications. ,vol. 2, pp. 371- 373 ,(1999) , 10.1016/S1387-7003(99)00096-9
Adi Yeori, Shimrit Gendler, Stanislav Groysman, Israel Goldberg, Moshe Kol, Salalen: a hybrid Salan/Salen tetradentate [ONNO]-type ligand and its coordination behavior with group IV metals Inorganic Chemistry Communications. ,vol. 7, pp. 280- 282 ,(2004) , 10.1016/J.INOCHE.2003.11.023
Michel Ephritikhine, A new look at the McMurry reaction Chemical Communications. pp. 2549- 2554 ,(1998) , 10.1039/A804394I
John E. McMurry, Carbonyl-coupling reactions using low-valent titanium Chemical Reviews. ,vol. 89, pp. 1513- 1524 ,(1989) , 10.1021/CR00097A007
Teruaki Mukaiyama, Toshio Sato, Junichi Hanna, REDUCTIVE COUPLING OF CARBONYL COMPOUNDS TO PINACOLS AND OLEFINS BY USING TiCl4 AND Zn Chemistry Letters. ,vol. 2, pp. 1041- 1044 ,(1973) , 10.1246/CL.1973.1041
Qingshan Tian, Chen Jiang, Yougui Li, Changsheng Jiang, Tianpa You, Experimental and theoretical investigation of the relationship between the stericstructure of Schiff bases and the diastereoselectivity of pinacol produced from benzaldehyde Journal of Molecular Catalysis A-chemical. ,vol. 219, pp. 315- 317 ,(2004) , 10.1016/J.MOLCATA.2004.05.015
Sónia Barroso, Pedro Adão, M. Teresa Duarte, Auke Meetsma, João Costa Pessoa, Marco W. Bouwkamp, Ana M. Martins, Chiral Diamine Bis(phenolate) TiIV and ZrIV Complexes – Synthesis, Structures and Reactivity European Journal of Inorganic Chemistry. ,vol. 2011, pp. 4277- 4290 ,(2011) , 10.1002/EJIC.201100470