A new and versatile method for iodofunctionalization of 1,3-dienes

1986

Abstract We wish to report the reactions of conjugated dienes with I(py) 2 BF 4 . This simple and general method allows the regiospecific 1,2-addition of iodine and a nucleophile to terminal dienes and the 1,4-addition to internal dienes.

ChemInform Abstract: 1,4-Regioselective Iodofunctionalizations of 1,3-Butadiene.

1989

1,3-Butadiene (I) is treated with a iodonium tetrafluoroborate in the presence of HBF4 and aqueous acetonitrile (II) or benzene (IV), yielding the 1,4-adducts (III) or (V).

ChemInform Abstract: Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ Ions: Neutral- and Acid-Promoted Transformations.

1988

A general method for the synthesis of N,O-aminals derived from primary aromatic amines is described. The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2CNAr or (H2CNHAr)+ equivalents. N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl)methane derivatives or N-benzylarylamines, respectively when heated in acidic media with pH control. Reduction of N,O-acetals with sodium cyanoborohydride has revealed that the C–O bond is broken exclusively in acidic media.

1,4-regioselective iodofunctionalizations of 1,3-butadiene

1988

Abstract Addition reactions of benzene and acetonitrile to 1,3-butadiene are described. This new iodofunctionalization process proceeds “via” iodonium ion-allylic cation equilibrium and gives regioselectively 1,4-adducts, which can be alternatively obtained by acid treatment of the 1,2-derivative 8 .

ChemInform Abstract: Acid-Mediated Reaction of Bis(pyridine)iodonium(I) Tetrafluoroborate with Aromatic Compounds. A Selective and General Iodination…

2010

Reaction of aromatic compounds with bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4) in the presence of HBF4 or CF3SO3H in CH2Cl2 at room temperature furnishes monoiodo derivatives with excellent regioselectivity and yields. Use of either acid gives comparable results with activated aromatics, whereas CF3SO3H is much more effective in the iodination of deactivated aromatics. © 1993 American Chemical Society.

Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ Ions: Neutral and Acid-promoted Transformations

1988

A general method for the synthesis of N,O-aminals derived from primary aromatic amines is described. The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2C=NAr or (H2C=NHAr)+ equivalents. N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl) methane derivatives or N-benzylarylamines, respectively when heated in acidic media with pH control. Reduction of N, O-acetals with sodium cyanoborohydride has revealed that the C-O bond is broken exclusively in acidic media.

A simple and general synthesis of symmetrical and unsymmetrical bis(arylamino)methanes. Reactions of N,O‐acetals with nitrogen bases

1988

Bis(arylamino)methanes 4 free of amine contamination have been efficiently synthesized from N,O-acetals 1 following three different methodologies. The first two are useful for symmetrical aminals and involve the decomposition of an N,O-acetal by a base (phenyllithium or a lithium arylamide) and trapping of the resulting methyleneamine 2 by the equimolar amount of the corresponding arylamine. The third method allows the preparation of either symmetrical or unsymmetrical aminals and consists of decomposing the starting N,O-acetal 1 by heating in vacuo in the presence of the desired arylamine. Ein einfacher und allgemeiner Zugang zu symmetrischen und unsymmetrischen Bis(arylamino)methanen. Rea…

An AM1 study on π-facial selectivity in Diels-Alder reactions of 2-aza-1, 3-dienes with azodienophiles

1994

Abstract A theoretical study of the π-facial selectivity in Diels-Alder reactions of chloro derivatives of 2-aza-1,3-dienes with azodienophiles has been carried out using the semiempirical AM1 method. Three transition structures for the model reaction of the diene 3 with the dienophile 4 were located. The Diels-Alder reaction of the non-substituted 2-aza-1,3-diene 6 with the trans -diimide was studied. All transition structures located show an important asynchronicity and the calculations reveal the presence of stereoelectronic effects. The predicted stereoselectivity is in agreement with the experimental evidence.

ChemInform Abstract: A Simple and General Synthesis of Symmetrical and Unsymmetrical Bis(arylamino)methanes. Reactions of N,O-Acetals with Nitrogen B…

1988

Bis(arylamino)methanes 4 free of amine contamination have been efficiently synthesized from N,O-acetals 1 following three different methodologies. The first two are useful for symmetrical aminals and involve the decomposition of an N,O-acetal by a base (phenyllithium or a lithium arylamide) and trapping of the resulting methyleneamine 2 by the equimolar amount of the corresponding arylamine. The third method allows the preparation of either symmetrical or unsymmetrical aminals and consists of decomposing the starting N,O-acetal 1 by heating in vacuo in the presence of the desired arylamine. Ein einfacher und allgemeiner Zugang zu symmetrischen und unsymmetrischen Bis(arylamino)methanen. Rea…

A study on the aminomercuration-nucleophilic demercuration of --1,5-cyclooctadiene; stereoselective synthesis of 2,6-disubstituted-9-aza bicyclo[3.3.…

1992

Abstract The aminomercuration of cis - cis -1,5-Cyclooctadiene with a series of mercury(II) salts followed by nucleophilic displacement of mercury by aromatic amines, water and nitrate ion has been studied. As a result, bicyclic triamines, aminoalcohols and nitrate esters have been obtained respectively in clean processes which occur under total stereoelectronic control by involvement of a tricyclic aziridium ion to afford a single stereoisomer in each case. The influence of the counter ion and the basicity of the amine on the tandem aminomercuration-demercuration is discussed.

ChemInform Abstract: Synthesis and Reactivity of β-Amino α,β-Unsaturated Oxa- and Thiazolines.

2010

Abstract A simple and efficient route to masked β-amino-α,β-unsaturated acids 3 by reaction of metalated oxa- and thiazolines with nitriles has been developed. The reactivity of 3 has also been explored.

I(py)2BF4, a New Reagent in Organic Synthesis: General Method for the 1,2-Iodofunctionalization of Olefins

1985

Iodine-Induced Stereoselective Carbocyclizations: A New Method for the Synthesis of Cyclohexane and Cyclohexene Derivatives

1988

Synthesis and reactivity of β-amino-α,β-unsaturated oxa- and thiazolines

1992

Abstract A simple and efficient route to masked β-amino-α,β-unsaturated acids 3 by reaction of metalated oxa- and thiazolines with nitriles has been developed. The reactivity of 3 has also been explored.

Acid-mediated reaction of bis(pyridine)iodonium(I) tetrafluoroborate with aromatic compounds. A selective and general iodination method

1993

Reaction of aromatic compounds with bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4) in the presence of HBF4 or CF3SO3H in CH2Cl2 at room temperature furnishes monoiodo derivatives with excellent regioselectivity and yields. Use of either acid gives comparable results with activated aromatics, whereas CF3SO3H is much more effective in the iodination of deactivated aromatics. © 1993 American Chemical Society.

ChemInform Abstract: Iodine-Induced Stereoselective Carbocyclizations - A New Method for the Synthesis of Cyclohexane and Cyclohexene Derivatives.

1989

ChemInform Abstract: Catalytic Aminomercuration of Olefins in a Tandem Aminomercuration-Deoxymercuration; One-Step Synthesis of Secondary N-Arylallyl…

1990

Abstract Allyl alcohols react with primary aromatic amines and stoichiometric amounts of mercury(II) tetrafluoroborate to give mixtures of mono- and diallyl anilines. However, the use of the tandem aminomercuration-deoxymercuration promoted by catalytic mercury(II) tetrafluoroborate allows to perform regiospecifically the monoallylation reaction with very high yields. A mechanism is proposed to account for the observed results.

Catalytic aminomercuration of olefins in a tandem aminomercuration-deoxymercuration; One-step synthesis of secondary n-arylallylamines from allylalco…

1990

Abstract Allyl alcohols react with primary aromatic amines and stoichiometric amounts of mercury(II) tetrafluoroborate to give mixtures of mono- and diallyl anilines. However, the use of the tandem aminomercuration-deoxymercuration promoted by catalytic mercury(II) tetrafluoroborate allows to perform regiospecifically the monoallylation reaction with very high yields. A mechanism is proposed to account for the observed results.

Synthesis and NMR configurational study of imidazo[2,1-b]thiazoles from 1H-1,4-diazepine-7(6H)-thiones

1993

Abstract A thermal intramolecular cyclization of 1-vinyl2,3-dihydro-3 H -imidazole-2-thiones to imidazo[2,1-b]thiazoles is reported. A heteronuclear correlation study of these systems was made in order to establish the configuration of the products.

Iod-induzierte stereoselektive Carbocyclisierungen – Beispiele für eine breit anwendbare, neue Methode zur Synthese von Cyclohexan- und -hexen-Deriva…

1988

I(py)2BF4, ein neues Reagens: allgemeine Methode für die 1,2-Iodfunktionalisierung von Olefinen

1985

A new electrophilic addition to acetylenes. Synthesis of 1,2-iodofunctionalized olefins

1986

Abstract Acetylenes react with bis(pyridine)iodo(I) tetrafluoroborate ( 1 ) in the presence of a wide variety of nucleophiles (F, Cl, Br, I, SCN, pyridine, OAc, anisole, H) to give 1,2-iodofunctionalized olefins ( 4 ).