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The reactions of 3-iodotropolone with styrenes (styrene, p-methoxystyrene, and 2-vinylpyridine), methyl acrylate, and allylic compounds (methyl 3-butenoate, 3-butenenitrile, 1-allyl-3,4-dimethoxybenzene, and 1-allyl-3,4-methylenedioxybenzene) were carried out, according to the modified Heck’s procedure, to give 3-styryl-, 3-(2-carboxyvinyl)-, and 3-(3-substituted 1-propenyl)tropolones, respectively. Similarly, 4-bromo- or 5-bromotropolone was made to react with these olefins to yield 4-styryltropolone or the corresponding 5-(2-substituted vinyl)- and 5-(3-substituted 1-propenyl)tropolones. Substitution of 2-chlorotropone by styrenes produced 2-styryltropones. Extension of the vinylation to 2-amino-6-bromoazulenes, ethyl 3-bromo-1-azulenecarboxylate, and diethyl 2-chloro-1,3-azulenedicarboxylate resulted in a similar substitution.

The reaction of 1,2-dihydronaphthalene, indene, and acenaphthylene with phenylpalladium chloride prepared in situ from phenylmercuric chloride and lithium chloropalladate in aqueous acetone afforded 2-phenyltetrarol, 2-phenylindanol, and 2-phenylacenaphthenol respectively, accompanying by the corresponding phenylated olefins. Acetoxyphenylation products were also obtained in the reactions in acetic acid. The configurations of these oxyphenylated compounds were determined to be trans.

The reaction of α- or β-methylstyrene with phenylpalladium chloride in aqueous acetone were studied. From cis- or trans-β-methylstyrene, a mixture of erythro and threo isomers of hydroxyphenylation products PhMeCHCHOHPh (VIa, VIb) and chlorophenylation products PhMeCHCHClPh (IVa, IVb) were obtained accompanying the phenylated olefins (I, II, and III). The main reaction product was the tertiary alcohol PhCH2C(OH)MePh (V). The reaction of α-methylstyrene with phenylpalladium chloride gave V exclusively. Phenylpalladium acetate and phenylpalladium bromide were used as phenylating agents. The yields of hydroxyphenylation products are in decreasing order: chloride>bromide>acetate.

The reaction of isoflavanone oxime (III), 7-methoxyisoflavanone oxime (IV), and 4′,7-dimethoxyisoflavanone oxime (V) with lithium aluminum hydride in ether for 20 hr under refluxing gave 3-phenyl-2,3,4,5-tetrahydro-1,5-benzoxazepine derivatives (XVII, XVIII and XIX) but not the expected 4-aminoisoflavans. When a similar reaction was carried out using flavanone oxime and 7-methoxyflavanone oxime, only 4-aminoflavans were obtained, and the rearrangement reaction observed in isoflavanone oximes did not occur. Therefore, it may be considered that, in the reaction of chromanone oximes and lithium aluminum hydride, the position (C2 or C3) and the size of the substituent exerts a remarkable influence on the rearrangement reaction, while the methoxyl group at the 7-position (para position to the oximino group) has little effect.

The reaction of nitrous acid and three 4-aminoisoflavan hydrochlorides (III, IV, and V) obtained by the catalytic hydrogenation of isoflavanone oximes, and the hydroboration of three isoflavenes (XII, XIII, and VIII), were investigated in the hope of finding a general method of synthesizing trans-isoflavan-4-ols. The reaction of III and IV with nitrous acid afforded the corresponding trans-4-ols, though in a poor yield, but that of V produced no expected compound, the corresponding isoflavene (VIII) being obtained instead. The hydroboration of XII, XIII, and VIII afforded the corresponding trans alcohols (VI, VII, and XIV) in good yields. In addition, it became clear that 4-aminoisoflavans obtained by the catalytic reduction of the oximino compounds possess the 3,4-cis configuration.

The synthesis and the stereochemistry of 4-chromanones and 4-chromanols with bulky substituents have been investigated. In 3-substituted chromanones, the t-butyl group exists mainly in the quasi-axial position, while the phenyl group is still in the quasi-equatorial environment. The preferred conformations of the isopropyl, and of the t-butyl group in cis- and trans-2-substituted chromanols, are equatorial, whereas trans-3-t-butylchromanol and its benzoate exist mainly as the conformations in which the t-butyl group is in the axial position. The conformational preference of these compounds can reasonably be explained by considering the steric interactions (A(1,3) strain, gauche, and diaxial repulsion) of these groups. The magnitude of the A(1,3) strain due to the hydroxyl group was estimated to be 1.3 kcal/mol.

trans-Isoflavan-4-ol was synthesized from chromene with phenylpalladium chloride in one step. Treatment of the alcohol with NBS gave isoflavone.