Enantioselective addition of diethylzinc to aldehydes catalyzed by titanium(IV) complexes of N-sulfonylated amino alcohols with two stereogenic centers
作者:Jing-Song You、Ming-Yuan Shao、Han-Mou Gau
DOI:10.1016/s0957-4166(01)00522-5
日期:2001.11
Bidentate N-sulfonylated aminoalcohols with one or two stereogenic centers were prepared and applied as chiral ligands in the titanium(IV)-catalyzed asymmetric addition of diethylzinc to aldehydes, affording excellent enantioselectivities of up to 98% e.e.
Dual Stereoselectivity in the Dialkylzinc Reaction Using (−)-β-Pinene Derived Amino Alcohol Chiral Auxiliaries
作者:Caitlin M. Binder、April Bautista、Marek Zaidlewicz、Marek P. Krzemiński、Allen Oliver、Bakthan Singaram
DOI:10.1021/jo802371z
日期:2009.3.20
morpholino group through a simple substitution reaction. 3-MAP was characterized by X-ray crystallography, which displayed the rigidity of the pinane framework. Amino alcohol 2-MAP was prepared from its trans isomer 2, which in turn was synthesized via hydroboration/oxidation of the morpholine enamine of (+)-nopinone. Two-dimensional NMR was used to characterize amino alcohol 2-MAP, and NOE was used to confirm
Synthesis of New Chiral Aliphatic Amino Diselenides and Their Application as Catalysts for the Enantioselective Addition of Diethylzinc to Aldehydes
作者:Antonio L. Braga、Marcio W. Paixão、Diogo S. Lüdtke、Claudio C. Silveira、Oscar E. D. Rodrigues
DOI:10.1021/ol034773e
日期:2003.7.1
[reaction: see text] A set of chiral aliphatic amino diselenides have been synthesized from readily available starting materials in a straightforward synthetic route via the ring-opening reaction of the parent aziridines. These ligands have been tested as catalysts for the enantioselective addition of diethylzinc to aldehydes. The influence of the alkyl group substituents on the stereoselectivity has
Optically active hydrazone and imine were found to act as effective ligands for enantioselectiveaddition of diethylzinc to aldehydes. This reaction provided optically active secondary alcohols with ee up to 71%.
d-Penicillamine derived thiazolidine ligands were prepared in a two-step synthetic sequence and used in the enantioselective alkylation of a variety of aromatic aldehydes with diethylzinc at room temperature. Excellent ee, up to >99%, and nearly complete conversions were observed. Structurally analogous l-cysteine derived thiazolidine ligands were also synthesized and tested for comparative purposes