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Daicel Chiralpak IA, IB, and IC, which are the polysaccharide-based chiral stationary phase (CSP) columns for high-performance liquid chromatography (HPLC), were applied in the separation of the non-enantiomeric isomeric mixtures obtained by the various allylation reactions and were highly effective in separating the regio- and (E)/(Z)-isomers in the allylation products. Due to the close structural similarity of the isomeric allylic compounds in the reaction mixtures, separations of the isomers are laborious and could not be accomplished by the conventional methods such as silica gel column chromatography, silica gel HPLC, preparative GPC, distillation, and so forth. This study has shown potential advantages of using the polysaccharide-based CSP columns in the separation of not only enantiomeric but also non-enantiomeric isomeric mixtures.

A series of monodentate ferrocenylphosphines, Fc3P (1a), Fc2PhP (1b), and Fc2ArP (1c; Fc = ferrocenyl, Ar = 3,4-methylenedioxyphenyl), were prepared, and their electronic and steric properties were quantitatively determined. By the IR measurements of their respective Ni(CO)3(phosphine) complexes, the electronic properties of the ferrocenyl group in organophosphines were estimated to be similar to those of primary alkyl groups. The ferrocenyl group is a better electron donor than a methyl group and a poorer donor than an ethyl group. The gold(I) chloride complexes of 1a–c were prepared and their X-ray crystal structures were determined. The %Vbur parameters for 1a–c were calculated using the X-ray structural data, and their ″Tolman cone angles″ were estimated. The steric influence of the ferrocenyl group in organophosphines was clarified to be larger than those of cyclohexyl, tert-butyl, and o-tolyl groups and is comparable to that of a mesityl group.

We report an efficient method for the preparation of synthetically valuable trisubstituted alkenylboronate esters through alkene isomerization of their readily available 1,1-disubstituted regioisomeric counterparts. Either stereoisomer of the target alkenylboronate motif can be obtained at will from the same starting material by employing different isomerization catalysts.

A series of ferrocene-fused planar-chiral N-tosyl-4-pyridones (S)-2b-d were prepared in enantiomerically pure forms. Starting with the chiral ferrocenyl acetals, 1-[(2S,4S)-4-methoxymethyl-1,3-dioxan-2-yl]-1',2',3',4',5'-R5-ferrocenes ((–)-3b, R = Me; (–)-3c, R = Ph; (–)-3d, R = Bn), N-tosylamino and formyl groups were introduced at the 1- and 2-positions of the ferrocene cores in (S)-11b-d with control of the planar chirality. After the reaction with ethynylmagnesium bromide, generated propargyl alcohol derivatives (S)-17 were treated with MnO2 and catalytic TBAI to give the planar-chiral pyridones by the iodide-catalyzed cyclization. This method is highly practical with a shorter and higher-yield sequence without using noble metal catalysts. Planar-chiral ferroco-pyridones (S)-2b-d were reacted with various Me3Si-NR'2 to give a library of ferrocene-fused 4-dialkylaminopyridines ((S)-1, DAAPs) in high yields as single-enantiomers by the detosylative amination. The cymantrene-fused DAAPs were also prepared in the same way. The library of the chiral DAAPs were examined in the two asymmetric reactions as organocatalysts, and some newly prepared Fc-DAAPs showed better enantioselectivity than the known species.

Readily available 3-bromopenta-2,4-dienyl esters (1x, acetate; 1y, benzoate; 1z, diethyl phosphate) were applied to the palladium-catalyzed reaction with various soft nucleophiles. The reaction proceeded through the twofold nucleophilic substitution via formal SN2'- and SN2-processes giving the various doubly functionalized allenes 2 in good yields. In the reactions of carboxylates 1x and 1y, the first substitution took place at the C-Br bond to form (allenyl)methyl ester intermediates 3. Because the second substitution on 3 proceeded faster than the first substitution on 1x or 1y, 3 were not isolable and C2-symmetric allenes 2 were obtained even in the presence of remaining 1x and 1y. On the other hand, the phosphate moiety was more reactive than the C-Br moiety in 1z. The initial products from 1z were 5-Nu-3-bromopenta-1,3-dienes 4 which were less reactive than 1z. Monosubstitution products 4 were isolable, and the stepwise introduction of two different Nu groups in C1-symmetric allenes 2 was realized starting with 1z under the controlled reaction conditions. By the use of a chiral palladium catalyst, axially chiral doubly functionalized allenes were obtained in up to 95% ee.

The three-component coupling reaction of 1,1-dibromoalkenes 1, vinylzinc chloride 2, and carbon soft nucleophiles 3 was realized in the presence of the catalytic palladium/Xantphos species, and 1,3-disubstituted allenic products 5 were obtained in yields of up to 77%. The successive two palladium-catalyzed processes, namely the cross-coupling reaction and the allylic substitution, assembled 5 from the easily accessible starting compounds.

The C2-symmetric tetralin-fused 1,4-diiodo-1,3-butadiene derivatives, (Z,Z)-2,3-di(1-iodoalkylidene)tetralin 1a-c, are atropisomeric and can be resolved into the two persistent axially chiral enantiomers by HPLC on a chiral stationary phase. The enantiomerically pure compounds can serve as chiral organocatalysts for dearomatizing spirolactonization to show good performances in up to 73 % ee.

Here we report the resolution of phosphorescent light-emitting iridium(III) bis[(4,6-difluorophenyl) pyridinato-N, C-2]-picolinate into its respective enantiomers by using chiral HPLC and the photo-induced transformation of the isolated enantiomers.