134223-83-9Relevant academic research and scientific papers
Highly enantioselective arylation of aldehydes and ketones using AlArEt2(THF) as aryl sources
Zhou, Shuangliu,Wu, Kuo-Hui,Chen, Chien-An,Gau, Han-Mou
supporting information; experimental part, p. 3500 - 3505 (2009/09/30)
A series of AlArEt2(THF) (Ar = Ph (la), 4-MeC6H 4 (1b), 4-MeOC6H 4 (1c), 4-Me 3SiC6H4 (1d), 2-naphthyl (le)) were synthesized from reactions of AlEt2Br(THF) with ArMgBr. In CDC13 solution, the 1H NMR spectra showed that AlArEt2(THF) compounds exist as a mixture of four species of formulas of AlAr xEt3-x (THF) (x = 0, 1, 2, or 3). AlArEt2(THF) compounds were found to be superior and atom-economic reagents for asymmetric aryl additions to organic carbonyls. Aryl additions of AlArEt2(THF) to aldehydes catalyzed by the titanium(IV) complex of (R)-H8-BINOL were efficient with a short reaction time of 1 h, affording aryl addition products as exclusive or main products in high yields and excellent enantioselectivities of up to 98% ee. Although ethyl additions to aldehydes occurred in minor extent, this study demonstrates that increasing the amount of AlArEt2(THF) from 1.2 to 1.4 or to 1.6 equiv significantly improved the aryl addition products of up to >99%. On the other hand, asymmetric arylations of AlArEt2(THF) to ketones employing a titanium(IV) catalyst of (S)-BINOL produced optically active tertiary alcohols exclusively in excellent enantioselectivities of up to 94% ee.
Preparation of 1,1-diphenylethanols by addition of organotitanium compounds to substituted aceto- and benzophenones
Dimitrov,Stanchev,Milenkov,Nikiforov,Demirev
, p. 228 - 232 (2007/10/02)
The 1,1-diphenylethanols 5a-h were prepared by the addition of phenyltitanium triisopropoxide (3) to 4-substituted acetophenones 1a-h. The titanium tetraalkoxide 7, formed in situ from 3 and 1a, forms complexes with up to two molecules of 1a, this was established by 13C-NMR. Preparation of the alcohols 5a-f was also carried out by the reaction of methyltitanium triisopropoxide (4) with 4-substituted benzophenones 2a-f.
