Bis(μ-oxo)–Dititanium(IV)–Chiral Binaphthyldisulfonate Complexes for Highly Enantioselective Intramolecular Hydroalkoxylation of Nonactivated Alkenes
作者:Wen-Bin Xie、Zhi Li
DOI:10.1021/acscatal.1c01146
日期:2021.5.21
A series of chiral 1,1′-binaphthyl-2,2′-disulfonic acids was designed, synthesized, and applied in a highlyenantioselective Ti-catalyzed intramolecular hydroalkoxylation of nonactivated alkenes. The catalyst is probably a complex between two chiral binaphthyldisulfonate ligands and a bis(μ-oxo)–dititanium(IV) core structure. The sulfonamide groups of the ligands and water are necessary for the catalysis
4-hydroxytetrahydropyran-2-one derivatives with general formula (I) are useful as cholesterol reducing agents as well as lipid reducing agents, serving as inhibitors of HMG-CoA reductase, and capable of inhibiting the biosynthesis of peroxidized lipids, and therefore effective for curing arteriosclerosis: ##STR1## wherein R.sub.1 represent hydrogen or a 2-tetrahydropyranyl group; R.sub.2 and R.sub.3 each represent hydrogen or an alkyl group having 1 to 6 carbon atoms; R.sub.4 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, an aralkyl group, an acyl group, an aroyl group or a substituted sulfonyl group; A represents --CH.sub.2 CH.sub.2 --, or --CH.dbd.CH--; and n is an integer of 1 or 2, and intermediates for synthesizing the 4-hydroxytetrahydropyran-2-one derivatives are disclosed.
Bi(OTf)3-catalyzed allylation of quinones with allyltrimethylsilane
作者:J.S Yadav、B.V.S Reddy、T Swamy
DOI:10.1016/s0040-4039(03)01130-4
日期:2003.6
p-Quinones react smoothly with allyltrimethylsilane in the presence of 2 mol%, of Bi(OTf)(3) under mild reaction conditions to afford the corresponding allyl substituted benzene derivatives, p-allylquinols and allyl substituted 1,4-naphthoquinones in excellent yields with high regioselectivity. This method is very useful for the direct introduction of an allyl functionality onto a quinone moiety. (C) 2003 Elsevier Science Ltd. All rights reserved.