Kenji Omata

Rhodium-catalyzed cross coupling of unactivated allenes and 1-alkynes

Abstract Mixture of HRh(CO)(PPh 3 ) 3 and Et 3 P catalyzes cross coupling reaction of unactivated allenes and 1-alkynes. CC bond formation takes place regioselectively at 2-position of allenes giving endo -( E )-enynes in high yields and selectivities. Added PEt 3 promotes the reaction and enhances the regio- and stereoselectivity.

Use of a diamagnetic lanthanide complex for extending the scope of NMR determination of absolute configuration by the modified Mosher's method

Abstract The reversal of the relative position of 1H NMR signals observed for diastereomeric MTPA esters and amides upon addition of La(hfaa)3 can be used for verification of the validity of the correlation model employed in the modified Moshers method. This verification extends the scope of the determination of absolute configurations using the Mosher method to substrates having only a few proton probes.

Use of Sm(III)–{1,2-propanediamine-N,N,N′,N′-tetra(α,α-dideuterioacetate)} complex for NMR determination of absolute configuration of each α-amino acid in peptide hydrolysate mixtures

(1)H NMR analyses of individual alpha-amino acids in their mixture were simultaneously conducted in the presence of Sm-(pdta-d(8)) in water: high regularity, promising for direct simultaneous determination of absolute configurations of each alpha-amino acids in peptide hydrolysate mixtures, was observed between absolute configuration and the induced shifts.

Determination of the absolute configurations of α-amino esters from the 19F NMR chemical shifts of their CFTA amide diastereomers

The CFTA method has proved to be useful for assigning absolute configuration of α-amino esters by 19F NMR.