Application of a Heterogeneous Chiral Titanium Catalyst Derived from Silica-Supported 3-Aryl H<sub>8</sub>-BINOL to Enantioselective Alkylation and Arylation of Aldehydes
derivative as a precursor, and the resulting silica-supported ligand (6 mol %) was employed in the enantioselectivealkylation and arylation of aldehydes in the presence of Ti(OiPr)4. The reactions using Et2Zn, Et3B, and aryl Grignard reagents all afforded the corresponding adducts in high enantioselectivities and yields. The silica-immobilized titanium catalyst could be reused up to 14 times without appreciable
Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform
作者:Tetsuya Yamamoto、Michiko Iizuka、Hiroto Takenaka、Tetsuo Ohta、Yoshihiko Ito
DOI:10.1016/j.jorganchem.2008.12.032
日期:2009.4
Arylboronic acids react with aldehydes and α,β-unsaturatedcarbonylcompounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform
Catalytic Enantioselective Arylation of Aldehydes by Using Functionalized Grignard Reagents Generated from Aryl Bromides
作者:Toshiro Harada、Daisuke Itakura
DOI:10.1055/s-0031-1289854
日期:2011.12
of functionalized diarylmethanols starting from aryl bromides and aldehydes. In the presence of (R)-3-(3,5-diphenylphenyl)BINOL (2 mol%) and titanium tetraisopropoxide, functionalized aryl Grignard reagents (FGArMgCl; FG = 3-F3C, 4-F3C, 3-Br, 3-CN, 4-CN), prepared in situ by treatment of the bromides with i-PrMgCl˙LiCl, undergo addition to aldehydes to give the corresponding functionalized diarylmethanols
Catalytic Enantioselective Synthesis of Diarylmethanols from Aryl Bromides and Aldehydes by Using Organolithium Reagents
作者:Yuya Nakagawa、Yusuke Muramatsu、Toshiro Harada
DOI:10.1002/ejoc.201001254
日期:2010.12
developed for preparing enantio-enriched secondary alcohols by starting from aryl bromides and aldehydes. Aryl bromides were first treated with BuLi, and the resulting aryllithium reagents were mixed with titanium tetraisopropoxide and magnesium bromide. The reaction of aldehydes with the resulting mixed titanium reagents, in the presence of 3-(3,5-diphenylphenyl)-H 8 -BINOL (2 mol-%) and titanium
Addition of AlMe3 to commercial THF solutions of RZnX (R = aryl, functionalised aryl, vinyl; X = Br, I) simultaneously promotes Schlenk equilibria (leading to competent nucleophiles) and the formation of an Al–Zn-ligand catalyst delivering 80–90% ee for Ar1CH(OH)Ar2 formation from aldehydes.