3,3'-Substituted BINOL's have been identified as suitable chiral ligands for the zirconium-catalyzed aldol-Tishchenko reaction of aromatic ketone aldols with aliphatic aldehydes. 1,3-anti-Diol monoesters were obtained in excellent yields, complete anti-diastereo-control, and enantioselectivities of up to 60% ee. (c) 2006 Elsevier Ltd. All rights reserved.
Synthesis of<i>anti</i>-1,3-Diols through RuCl<sub>3</sub>/PPh<sub>3</sub>-Mediated Hydrogenation of β-Hydroxy Ketones: An Alternative to Organoboron Reagents
Hydrogenation of enantioenriched β-hydroxyketones promoted by the catalyst generated in situ from commercially available and inexpensive RuCl3 and PPh3 under hydrogen pressure allowed the efficient preparation of a variety of anti-1,3-diols in good yields and with a high level of diastereoselectivity. This method should be an interesting alternative to organoboronreagents for the diastereoselective
New Protecting Groups for 1,2-Diols (Boc- and Moc-ethylidene). Cleavage of Acetals with Bases
作者:Xavier Ariza、Anna M. Costa、Montserrat Faja、Oriol Pineda、Jaume Vilarrasa
DOI:10.1021/ol0062289
日期:2000.9.1
[reaction: see text] 1,2-Diols react at rt with alkyl propynoates, in the presence of 4-dimethylaminopyridine, to give cyclic acetals which are quite stable to acid-catalyzed hydrolysis or methanolysis. 1,3-Diols and 1, 4-diols do not form acetals with alkyl propynoates under the same conditions. Deprotection is accomplished with bases (via elimination and addition/elimination steps).