Ultimate Sidebar

Synthesis of chiral vanadium phosphonates and their catalytic activity.

300 38
Treatment of Cl2P(O)CH2Ph with S(-)-1,1 '-binaphthyl-2,2'-diol, S(-)BINOL, in the presence of two equivalents of triethylamine, afforded (S(-)BINOL)P(O)CH 2Ph in high yield. Treatment of (S(-)BINOL)P(O)CH 2Ph with butyllithium and alkyl halides (RX = Mel, EtI, allylBr, PhCH 2Br) was found to proceed with good yields (up to 94%) and good diastereoselectivities (up to 91:9). This demonstrates that BINOL is a good chiral auxiliary for the alkylation of lithium-stabilized phosphonates. Upon purification by column chromatography, the chiral auxiliary from (S(-)BINOL)P(O)CHMePh- S was cleaved under basic conditions and enantiopure (HO)2P(O)CHMePh- S was isolated.; Treatment of vanadium starting materials with chiral and achiral phosphonic acids and phosphonates provided the soluble [BuPPh3]4[(V 2O2(OH)2)6(O3PR)8] R = CH(CH2Ph)Pr and CH(Et)Pr, [(VO)6(O3PR) 8{lcub}Cl{rcub}] R = CH2Ph, CHMePh-S, and [(V 14O22)(OH)4(O3PR)8] 6- with R = CHEtPr, CH(CH2Ph)Pr, and CH(Me)Ph- S cage complexes. These are the first reported examples of vanadium phosphonate cage molecules synthesized with racemic and enantiopure phosphonate starting materials. In addition, treatment of V2O 5 with (HO)2P(O)R in ethanol, where R = Ph and CHMePh- S, afforded (VO)(O3PR)·yEtOH·xH2O. (VO)(O3PCHMePh-S)·H2O is the first layered vanadium phosphonate material synthesized using an enantiopure phosphonic acid. These materials were tested for catalytic activity in the asymmetric epoxidation of geraniol and cinnamyl alcohol.
来源: https://www.10026.com/xueshuxuewei_thesis/zou9yb.html [免费获取该论文&期刊全文请访问原址]
Subscribe to our newsletter
Sign up here to get the latest news, updates and special offers delivered directly to your inbox.
You can unsubscribe at any time

Leave A Reply

Your email address will not be published.