کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1312849 975507 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Modification of alkoxo ligands of BINOL–Ti ladder: Isolation and X-ray crystallographic analysis
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Modification of alkoxo ligands of BINOL–Ti ladder: Isolation and X-ray crystallographic analysis
چکیده انگلیسی

The stable binaphthol–titanium ladder complexes have been successfully prepared by using bulky alkoxo ligands. From the secondary OR ligand (cyclohexyloxo, 2,4-dimethyl-3-pentyloxo or 2-adamantyloxo) and terially OR ligand (tert-butyloxo, 1-adamantyloxo), partial hydrolysis proceeded to give the μ3-oxo titanium complexes. The use of [Ti(BINOLato)(OEt)2]n made it possible to prepare the Ti(BINOLato)(OR)2 complexes using alcohols (ROH) of high boiling point (R = cyclohexyl, 2-adamantyl, 1-adamantyl). X-ray analyses of [(R)-1,1′-bi-2-naphtholato]bis(O-2,4-dimethyl-3-pentyloxo)titanium and [(R)-3,3′-dimethyl-1,1′-bi-2-naphtholato]bis(2-adamantyloxo)titanium showed a good agreement with the estimated ladder complexes. The catalytic activity of BINOL–Ti catalyst analogues, obtained by partial hydrolysis of Ti(BINOLato)(OR)2 with wet MS 4A was studied in asymmetric glyoxylate-ene reaction by two methods. Moderate to good chemical yields and enantioselectivities were obtained.

Stable binaphthol (BINOL)-titanium ladder complexes were successfully prepared using bulky alkoxo (OR) ligands. The catalytic activity of BINOL-Ti catalyst analogues, obtained by partial hydrolysis of Ti(BINOLate)(OR)2 with wet MS 4A was thus studied in asymmetric glyoxylate-ene reaction to give good to moderate levels of enantioselectivity and yield (98% ee, 73% yield).Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Inorganica Chimica Acta - Volume 359, Issue 13, 1 October 2006, Pages 4159–4167
نویسندگان
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