α-Hydroxy ketones are frequently involved in biologically important compounds and,therefore,the determination of the stereochemistry of these structural elements has attracted the attention in natural products chemis...α-Hydroxy ketones are frequently involved in biologically important compounds and,therefore,the determination of the stereochemistry of these structural elements has attracted the attention in natural products chemistry.In this paper a simpler Mosher′s method was developed from the modified Mosher′s method.It only need one configuration of MTPA to determine the absolute configurations of four α-hydroxy ketones with their（S）-and（R）-MTPA esters using（）1H NMR.The signals of protons on the same side with phenyl ring will be in the higher field than those of on the different side ones.Consequently according to the model the main configuration of compounds 1,2,3 and 4 were determined as S,R,R and S, respectively.展开更多
Chiral camphor derivatives 3a^3e are efficiently prepared from chiral intermediate silyl enol ether of camphor derived from cheap and natural D-(+)- camphor with excellent chemical yield(87~96%) and high enatioselecti...Chiral camphor derivatives 3a^3e are efficiently prepared from chiral intermediate silyl enol ether of camphor derived from cheap and natural D-(+)- camphor with excellent chemical yield(87~96%) and high enatioselectivity(d.e.96~99%).These conpounds are identified by 1HNMR,IR and LC-MS spectral.展开更多
文摘α-Hydroxy ketones are frequently involved in biologically important compounds and,therefore,the determination of the stereochemistry of these structural elements has attracted the attention in natural products chemistry.In this paper a simpler Mosher′s method was developed from the modified Mosher′s method.It only need one configuration of MTPA to determine the absolute configurations of four α-hydroxy ketones with their（S）-and（R）-MTPA esters using（）1H NMR.The signals of protons on the same side with phenyl ring will be in the higher field than those of on the different side ones.Consequently according to the model the main configuration of compounds 1,2,3 and 4 were determined as S,R,R and S, respectively.
文摘Chiral camphor derivatives 3a^3e are efficiently prepared from chiral intermediate silyl enol ether of camphor derived from cheap and natural D-(+)- camphor with excellent chemical yield(87~96%) and high enatioselectivity(d.e.96~99%).These conpounds are identified by 1HNMR,IR and LC-MS spectral.
