Naomichi Furukawa

Ligand coupling through σ-sulfurane — complete retention of configuration of 1-phenylethyl group in the reaction of 1-phenylethyl 2-pyridyl sulfoxide with grignard reagent1

Abstract The reaction of benzyl or 1-phenylethyl 2-pyridyl sulfoxide with Grignard reagent proceeds via a σ-sulfurane as an intermediate to give the coupling product, 2-benzylpyridine or 2-(1-phenylethyl)pyridine in quantitative yield. Stereochemistry for this reaction is complete retention at the benzylic carbon atom.

A convenient preparation of bipyridines through ligand coupling reaction with a-sulfurane formed by treatment of methyl 2-pyridyl sulfoxide with grignard reagents

Abstract 6-substituted 2-methylsulfinyl pyridines react with Grignard reagents to afford 6,6′-disubstituted-2,2′-bipyridines (substituents: MeS, Cl, Br, H) in fair yields.

Preparation of pyridyl grignard reagents and cross coupling reactions with sulfoxides bearing azaheterocycles

Abstract Pyridyl Grignard reagents were prepared from the corresponding iodopyridine and EtMgBr. New cross coupling reactions of the Grignard reagents with azaheterocycles took place on the sulfinyl sulfur atom to afford biazaheteroaryls.

One step synthesis of aziridines by the Michael type addition of free sulfimides: Preparation and absolute configuration of optically active acylaziridines

Abstract The Michael type additions of diphenyl N-unsubstituted sulfimide (free sulfimide) to various electrophilic olefins were carried out. The reaction with cis - and trans -dibenzoylethylene, dimethyl-fumarate, dimethylmaleate, benzalacetophenone and benzalacetone gave mainly the corresponding trans -2-acylaziridines and trans -enaminoketones. However, phenyl vinyl sulfone or acrylonitrile afforded not the corresponding aziridine but diphenyl-N-2-cyano or N-2-phenylsulfonylethylsulfimide, a simple Michael adduct When optically active (+)-( R )- o -methoxyphenyiphenyl free sulfimide was treated with such an α,β-unsaturated carbonyl compound as benzalacetopbenone, an optically active 2-acylazindine, i.e., (-)- trans -2-benzoyl-3-phenylaziridine was obtained in ca 30% optical purity and its absolute configuration was assigned as (2 R ,3 S ) upon chemical transformation to the configuration-ally known 2-phenyl-2-benzoylamino-1-ethanol or by comparing its CD spectrum with that of (1 R ,2 R )-1-phenyl-2-benzoyl-cyclopropane. Meanwhile, (-)-( S )- o -methoxyphenylphenyl free sulfimide was found to react with benzalacetophenone to afford (+)-trans-2-benzoyl-3-phenylaziridine of 25% optical purity. Effects of solvent and temperature on both die distribution of the products ratio and the optical yield were examined.

Reactions of pyridyl and quinolyl sulfoxides with grignard reagent: A convenient preparation of pyridyl and quinolyl grignard reagents

Abstract 3-,4-Pyridyl and 4-quinolyl Grignard reagents were generated by the reaction of the corresponding phenyl sulfoxides with PhMgBr and give the adducts upon treatment with various aldehydes and ketones. The stereochemistry for the reaction was investigated.

Synthesis, stereochemistry, and circular dichroism of optically active o-substituted diphenyl sulphilimines and related compounds☆

Abstract Optically active o -substituted diphenyl N-substituted sulphilimines are readily synthesised by the reaction of the corresponding sulphides and t-butyl hypochlorite in the presence of l -menthol and amide anions. (−)-N- p -Tolylsulphonylsulphilimines ( 1 , 2 ) obtained were converted to the corresponding (−)-N-unsubstituted sulphilimines ( 8 , 9 ) by treating them with concentrated sulphuric acid. When (−)-S- o -anisyl S-phenyl N-(unsubstituted) sulphilimine ( 8 ) was treated with acylating agents or acrylonitrile, the corresponding optically active (−)-N-substituted sulphilimines were prepared with complete retention at sulphur. The absolute configuration of (−)-S- o -anisyl S-phenyl N- p -tolylsulphonylsulphilimine ( 1 ) was determined by converting it to (+)-S- o -anisyl sulphoxide ( 17 ). CD curves of (−)- o -substituted diarylsulphilimines exhibited a negative Cotton effect at around 270–285 nm, which was assigned to ( S )-configuration at sulphur by comparing with the analogous sulphoxides. The substituent on the imino group of the sulphilimine gave no appreciable effect on the CD behavior and the lack of substituent effect was considered to be due to the semi-polar character of the S(IV)-N bond. Unusual effect of o -methoxy group on the CD curves was discussed in connection with solvent effect. Mechanism of this asymmetric synthesis has been investigated, and it has become apparent that the diastereomeric menthoxysulphonium chloride was an excess of ( RR )-configuration was formed initially and the amide anion attacks the S atom of the salt with net inversion.

A new source for generation of benzyne and pyridyne: Reactions of O-halophenyl (or 3-bromo-4-pyridyl) phenyl sulfoxides with grignard reagants

Abstract o-Chloro- and o-bromophenyl phenyl sulfoxides and (3-bromo-4-pyridyl) phenyl sulfoxide were treated with Grignard reagents to generate benzyne (or 3,4-pyridyne) in THF. The o-iodophenyl derivative, on the other hand, gave mainly o-(arylsulfinyl)phenyl Grignard reagent.

Transition metal induced selective alkaline metal ion transport by asynthethic ionophore with double recognition sites for metals

A new series of linear ionophores 1 with double recognition sites for metals was prepared. Selectivity of ion transport for alkaline metalwas enhanced in the presence of transition metal.

LIGAND EXCHANGE AND LIGAND COUPLING VIA THE σ-SULFURANE INTERMEDIATE IN THE REACTION OF ALKYL 2-PYRIDYL SULFOXIDE WITH GRIGNARD REAGENTS: CONVENIENT PREPARATION OF 2,2′-BIPYRIDINES

Abstract The reaction between methyl 2-pyridyl sulfoxide (1) with Grignard reagents afforded 2,2′-bipyridine (2) in moderate yield. The reaction is considered to involve initial ligand exchange to generate 2-pyridylmagnesium halide which in the subsequent step attacks the original sulfoxide to form the σ-sulfurane that undergoes ligand coupling to afford 2. The reaction of t-butyl 2-pyridyl sulfoxide (3) with C6H5MgBr, however, gave only 2-phenylpyridine (4). This may be due to steric hindrance to the initial ligand exchange. Formation of 2 is a convenient process for preparation of 2,2′-bipyridines bearing various substituents.

Preparation of N-p-tosylaldimines by the intramolecular photo-imino group migration of naphtho[1,8-de]dithiin-1-N-tosylsulfilimines

Abstract Naphth[1,8- de ]dithiin-1- N -tosylsulfilimines ( 4 ) were prepared by the reaction of naphtho[1,8- de ]dithiins with chloramine-T. Photolysis of 4 undergoes intramolecular imino group rearrangement to give N -tosylaldimines quantitatively together with naphthalene-1,8-dithiole.