Hisakazu Miyamoto

Resolution of hydrocarbons by inclusion complexation with a chiral host compound

Abstract Some racemic unsaturated hydrocarbons, 3- and 4-methyl and 4-vinylcyclohexene, bicyclo[4.3]nonane-2,5-diene, and 3-chloro- and 3,4-dichloro-1-butene were resolved as inclusion complex crystals with a chiral host compound derived from tartaric acid. The inclusion complexation, purified by repeating recrystallization from ether twice and decomposed by heating in vacuo, gave optically active hydrocarbons of 28–75% ee by distillation. The optical resolution by inclusion complexation in a water suspension medium and by fractional distillation in the presence of a chiral host was also applied to these hydrocarbons.

Carboncarbon bond formation using bismuth in a water medium

In the presence of bismuth and ammonium chloride, allyl halides were found to react with aldehydes in a water medium at room temperature to give the corresponding homoallylic alcohols.

Formation of racemic compound crystals by mixing of two enantiomeric crystals in the solid state. Liquid transport of molecules from crystal to crystal

Mixing of powdered (-)- and (+)-enantiomer crystals in the solid state gives crystals of the racemic compound. This racemic crystal formation was followed by IR spectral measurement of a 1∶1 mixture of (-)- and (+)-enantiomer crystals as a Nujol mull. As the formation of racemic crystals proceeds, the OH absorptions of the enantiomer disappear gradually and new OH absorptions due to the racemic compound appear. The formation of racemic crystals from enantiomer crystals has been studied for various kinds of chiral compounds: 2,2′-dihydroxy-1,1′-binaphthyl (1) and its derivatives, 10,10′-dihydroxy-9,9′-biphenanthryl (4), 2,2′-dihydroxy-4,4′,6,6′-tetramethylbiphenyl (5) and its derivatives, 4,4′-dihydroxy-2,2′,3,3′,6,6′-hexamethylbiphenyl (8), 1,6-di(o-chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol (11) and its derivatives, trans-4,5-bis[hydroxy(diphenyl)methyl]-2,2-dimethyl-1,3- dioxacyclopentane (17) and its derivatives, tartaric acid (20) dimethyl tartrate (21), malic acid (22), mandelic acid (23), and norephedrine (24). These molecular movements and blending occur rapidly in the presence of liquids such as liquid paraffin (Nujol), seed oils such as olive, coconut, rapeseed and soybean oil, artificial oil such as silicone oil and water, although the same movement also occurs in the absence of the liquid. For example, keeping a mixture of powdered (-)-1 (1a) and (+)-1 (1b) at room temperature for 48 h gives racemic crystals (1c). However, molecular aggregation sometimes occurs in solution but not in the solid state. For example, recrystallization of (-)-16 (16a) and (+)-16 (16b) from solvent gives racemic crystals of 16c, although mixing of these two components as powders in the presence of liquid does not give 16c. In order to determine the mechanism of the molecular movement in the solid state, X-ray crystal structures of optically active and racemic compounds and also the molecular movements from optically active crystal to racemic crystal have been studied.

Mechanism of asymmetric photocyclization of α-oxoamides

The molecules of N,N-diisopropylarylglyoxylamides, 1, are converted into the corresponding β-lactams, 2, on exposure to UV light in the solid state. However, the chemical and optical yields of the photocyclization are quite different among the crystals. The crystal structures of the three positional isomers 1a–c as reactants and the photoproduct 2b derived from 1b are determined by X-ray structure analysis: (1a)o-chlorophenyl-N,N: diisopropylglyoxylamide; (1b)m-chlorophenyl-N,N-diisopropylglyoxylamide; (1c)p-chlorophenyl-N,N-diisopropylglyoxylamide; (2b) 3-(m-chlorophenyl)-3-hydroxy-N-isopropyl-4,4-dimethylazetidin-2-one. The reactivity and enantioselectivity of the reactions are discussed on the basis of the structures and the packing potential energy calculated.

Formation by mixing of chiral host–achiral guest inclusion complexes in which the guest molecules are arranged in a chiral form. Production of optically active photocyclisation compounds by irradiation of the inclusion complexes

Mixing of powdered chiral hosts and achiral N,N-dialkylphenylglyoxylamide guest compounds gives inclusion complexes in which the latter molecules are arranged in a chiral form, although such complexes are not obtained by recrystallisation: the chirality of the guest compounds are frozen by photoreaction which gives optically active β-lactams and oxazolidinones.

Formation of chiral β-lactams by photocyclisation of achiral N,N-diisopropylarylglyoxylamides in their chiral crystalline form

A variety of N,N- diisopropylarylgIyoxylamides formed chiral crystals in which the originally symmetrical molecules were arranged in a chiral form. Photoreaction of the chiral crystals gave optically active β-lactam derivatives.

Preparation of optically active cis-4-methylcyclohex-4-ene-1,2-dicarboximides by a combination of Diels–Alder reaction and complexation with optically active hosts and enantioselective Diels–Alder reaction in inclusion crystals in a water suspension medium

Optically active Diels–Alder adducts were prepared using a one-pot preparative method and enantioselective Diels–Alder reaction with optically active hosts in a water suspension medium.

Enantioselective Inclusion Complexation by the Chiral Host and Photocyclization Reaction

Abstract The chiral host 1 derived from tartaric acid formed the 1:1 inclusion complex with 2 by incorporating one of the enantiomers of 2 into the complex crystal. The irradiation of 2 gave optically pure product 3. The host 1 formed the 2:1 inclusion complex with the prochiral guest 4. The irradiation of this complex gave optically pure 5. In order to elucidate the enantioselective inclusion complexation and the stereospecific control of the photocyclization reaction by host 1, the X-ray crystallographic study of 1·2, 1·4 and 5 have been undertaken. All structures were solved by direct methods and refined by full-matrix least-squares refinement to give final R values of 0.055 for 1·2, 0.040 for 1·4 and 0.049 for 5. Each host molecule has one O-H—O intramolecular hydrogen bond and the same conformation. The enantioselective complexation in 1·2 will be attained by the specific host-guest interactions observed in the complex crystal, allowing an easy and straightforward method to prepare the optically pure...

Efficient optical resolution of cis-4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, cis-4-methylcyclohex-4-ene-1,2-dicarboximide, and their derivatives by complexation with optically active host compounds derived from tartaric acid

Optically pure enantiomers of cis-4-methylcyclohex-4-ene-1,2-dicarboxylic anhydrides, cis-4-methylcyclohex-4-ene-1,2-dicarboximides and 3-oxabicyclo[4.3.0]non-7-en-2-ones have been obtained by optical resolution through enantioselective inclusion complexation with optically active host compounds derived from tartaric acid. Kinetic resolution of cyclohex-4-ene-1,2-dicarboximides and cyclohexane-1,2-dicarboximides by way of enantioselective hydrolysis is also reported.

ENANTIOSELECTIVE PHOTOREACTION IN INCLUSION CRYSTAL

Abstract Mixing of powdered chiral hosts and achiral guest compounds gives inclusion complexes in which the latter molecules are arranged in a chiral form. Freezing of the chirality of the guest compounds by photoirradiation in the solid state gives optically active photoreaction products.