Chiral organosilicon compounds in asymmetric synthesis of chiral 1,3-diols
摘要:
Chiral 1,3-diols can be prepared in high enantiomeric purity (>99% ee) from the reactions of the chiral silylcarbanion 2 with epoxides followed by oxidative cleavage of the carbon-silicon bond with hydrogen peroxide. The absolute configurations of some of the chiral 1,3-diols were determined by circular dichroism (CD).
Chiral organosilicon compounds in asymmetric synthesis of chiral 1,3-diols
摘要:
Chiral 1,3-diols can be prepared in high enantiomeric purity (>99% ee) from the reactions of the chiral silylcarbanion 2 with epoxides followed by oxidative cleavage of the carbon-silicon bond with hydrogen peroxide. The absolute configurations of some of the chiral 1,3-diols were determined by circular dichroism (CD).
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
alternative to the commonly used Evans' reagent for the diastereoselective reduction of beta-hydroxy ketones is reported. Thus, ruthenium-mediated hydrogenation of enantioenriched beta-hydroxy ketones using RuCl3 associated to achiral monophosphines allowed the preparation of a series of 1,3-anti-diols in good yields and with a high level of diastereoselectivity. A short screening of ligands pointed out PPh3