A series of polysaccharide-based chiral stationary phase (CSP) columns, Daicel Chiralpak IA, IB, and IC, were applied in the separation of the nonenantiomeric isomers of various organometallic compounds and were found to be highly effective in recognizing isomers of minor structural differences. The CSP columns have succeeded to separate the double-bond regioisomers in bridged (η 5formylcyclopentadienyl)manganese(I) dicarbonyl complexes 1a/1b, the structural isomers of methylbutenylferrocene derivatives in 2a/2b and 3a/3b, and the geometrical isomers of the (2-methyl-2-butenyl)ferrocenes in (Z)/(E)-3b. Due to the close similarity of the isomeric compounds in these mixtures, separations of the components are extremely difficult and could not be attained by conventional methods such as silica gel column chromatography, silica gel HPLC, recrystallization, distillation/sublimation, etc. Clearly, the polysaccharide-based CSP columns have unique advantages in separation/purification technology, and this study has shown potential usefulness of the CSP columns in separation of not only enantiomeric but also nonenantiomeric mixtures. Figure 1. Nonenantiomeric isomeric pairs of organometallic complexes 1a/1b, 2a/2b, and 3a/3b examined in this report. Article pubs.acs.org/Organometallics

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The treatment of easily accessible o-(1-hydroxy-2alkynyl)-N-tosylanilides 1 with excess manganese(IV) oxide in the presence of substoichiometric tetrabutylammonium iodide (TBAI) in chloroform (or in the absence of TBAI in dimethylformamide, DMF) promoted a sequential oxidation/intramolecular hydroamination to give 4-quinolones 3 and/or (Z)-2-alkylidene-3-oxindoles (Z)-4 in good yields. Possibly, MnO 2 played dual roles as an oxidant and as a Lewis acidic activator of intermediary ynones 2. The product distributions between 3 and (Z)-4 could be controlled by the choice of solvents.

A C 1 -symmetric chiral bisphosphine, FcPh-Binap (1), which possesses a single diferrocenylphosphino moiety together with a conventional Ph 2 P-substituent, was prepared in enantiomerically pure forms. Ligand 1 is sterically less demanding than Fc-Segphos (A), which has two diferrocenylphosphino groups, and showed higher activity than A in the rhodiumcatalyzed asymmetric conjugate addition of phenylboronic acid to 2-cyclohexenone. Ligand 1 was applied in the two palladium-catalyzed asymmetric reactions, namely the synthesis of axially chiral allenes and the intermolecular Heck reaction, and displayed higher enantioselectivity than parent Binap. The Pd/(R)-1 species showed up to 47% ee enhancement over the Pd/(R)-Binap catalyst in the former reaction and up to 39% ee enhancement in the latter.

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