Z. Yoshida

Arylation and vinylation of 2-carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide catalyzed by palladium

Abstract By the palladium catalysis 2-carboethoxyethylzinc iodide reacts with aryl iodides and vinyl iodides or triflates to provide the coupling products (ethyl 3-arylpropionates and ethyl 4-pentenoates, respectively) in satisfactory yields. The similar coupling reaction is obserbed for the reaction with 3-carboethoxypropylzinc iodide.

Haloamidation of 3-hydroxy-4-pentenylamides: stereoselective synthesis of cis-1-halomethyl-2-hydroxypyrrolidines

Abstract Haloamidation of N-p-toluenesulfonyl 3-hydroxy-4-pentenamides, irrespectively of substitution pattern, provides N-p-toluenesulfonyl cis-1-halomethyl-2-hydroxypyrrolidines with high selectivity (⩾95 %) and in high yield.

Regiocontrolled 1,2-, 1,4-, and 1,6-additions of organometallics to unsaturated thioamides

Abstract 1,4-Addition of allyllithiums to α,β-unsaturated thioamides and 1,4-(kinetic) and 1,6-(thermodynamic)regiocontrolled additions of lithium enolates to thiosorbamide are reported.

The regioselective S → C and S → N allylic rearrangement of S-allylthioimidate

Abstract The regioselective S → C and S → N allylic rearrangements of S-allylthioimidates are realized by thermolysis (l60∼200°C) or palladium (II) catalysis (l∼l0 mol% in refluxing THF), respectively.

1,4-addition reaction of organometallics to α,β-unsaturated sec-thioamides

Abstract Preparation of α,β-unsaturated thioamides and their reactions (1,4-addition and β′-lithiation) with organometallics are described.

Synthesis and Photoreaction of 1,2,3,4-Tetra-t-butylnaphthalene: A Highly Crowded Naphthalene Derivative and Its Valenceisomers

Abstract 1,2,3,4-Tetra-t-butylnaphthalene ( 2 ), a highly crowded naphthalene derivative, has been synthesized. Upon irradiation, 2 underwent photovalence isomerization to afford 1,2,5,6-tetra-t-butyl-3,4-benzo-3-tricyclo[3.1.0.0 2,6 ]-hexene ( 3 ). The synthesis of 1,4,5,6-tetra-t-butyl-2,3-benzo-2,5-bicyclo[2.2.0]hexadiene ( 1 ), which was used for the synthesis of 2 , is also described.

Remote reformatsky reaction: reaction of β-, γ-, and δ-zinc esters with aldehydes

Ethyl β-, γ-, and δ-zinc esters react with aldehydes to provide ethyl γ-, δ-, and Iµ-hydroxy esters.

Generation of sec-thioamide dianions and their regioselective reaction with electrophiles.

Abstract The enolates of sec-thioamides 8 , which are generated by three different methods (scheme II and equation 1), are alkylated selectively at the α-carbon to the thiocarbonyl group. The unusual β′-lithiation to provide an intermediate 11 is observed for N-methyl-α, β-dimetylthioacrylamide and N-methyl-thiocyclohexenecarboxamide.

Threo selective cross aldol condensation with thioamide enolates generated by a michael addition of organometallics to unsaturated thioamides

Abstract Crotonothioamide, sorbothioamide, and cinnamothioamide undergo a threo selective aldol condensation via their enolates generated by a Michael addition of organometallics.

Electronic spectra and structures of organic π-systems

Semiempirical SCFMO calculations have been carried out on heterocyclic π-systems such as benzoxazole, benzotriazole, γ-pyrone, pyridonimine, pyridonemethide, benzothiazole and so on. A new modification of the Wolfsberg-Helmholz formula has been introduced in the evaluation of the core resonance integrals. The calculated transition energies are in good agreement with the experimental data.