Interaction of 1,3,2,4-benzodithiadiazines with aromatic phosphines and phosphites

Although an interaction between hydrocarbon and fluorocarbon 1,3,2,4-benzodithiadiazines (1 ) and P(C6H5)3 continuously produces chiral 1,2,3-benzodithiadiazol-2-yl iminophosporanes (2; in this work, 5,7-difluoro derivative 2a ) via 1:1 condensation, an interaction between 1 and other PR3 reagents gives different products. With R [DOUBLE BOND] OC6H5 and both hydrocarbon and fluorocarbon 1, only X=P(OC6H5)3 (X = S, O) were identified in the complex reaction mixtures by 13С and 31Р NMR and GC-MS. With R = C6F5, no interaction with the archetypal 1 was observed but catalytic addition of atmospheric water to the heterocycle afforded 2-amino-N-sulfinylbenzenesulfenamide (4 ). With electrophilic B(C6F5)3 instead of nucleophilic P(C6F5)3, only adduct H3N→B(C6F5)3 and a new polymorph of C6F5B(OH)2 were isolated and identified by X-ray diffraction (XRD). A molecular structure of 2a was confirmed by XRD, and the π-stacked orientation of one of phenyl groups and heterocyclic moiety was observed. This structure is in general agreement with that calculated at the RI-MP2 level of theory, as well as at three different levels of DFT theory with the PBE and B3LYP functionals. Mild thermolysis of 2a in a dilute decane solution gave persistent 5,7-difluoro-1,2,3-benzodithiazolyl (3a ) identified by EPR in combination with DFT calculations

A new type of C+⋯Hδ−(C=) bond in adducts of vinyl carbocations with alkenes

Abstract By X-ray diffraction analysis and IR spectroscopy, it was established here that vinyl carbocations C3H5 +/C4H7 + with carborane counterion CHB11Cl11 − form stable monosolvates C3H5 +⋅C3H6/C4H7 +⋅C4H8 with molecules of alkenes C3H6/C4H8. They contain molecular group =C+⋯Hδ−–Cδ+= with a new type of bond formed by the H atom of the H–C= group of the alkene with the C atom of the C+=C group of the carbocation. The short C+----Cδ+ distance, equal to 2.44 Å, is typical of that of X----X in proton disolvates (L2H+) with an quasi-symmetrical X–H+⋯X moiety (where X = O or N) of basic molecule L. The nature of the discovered bond differs from that of the classic H–bond by an distribution of electron density: the electron–excessive Hδ− atom from the (=)C–H group of the alkene is attached to the C+ atom of the carbocation, on which the positive charge is predominantly concentrated. Therefore, it can be called an inverse hydrogen bond

Interaction of Vinyl-Type Carbocations, C₃H₅⁺ and C₄H₇⁺ with Molecules of Water, Alcohols, and Acetone

X-ray diffraction analysis and IR spectroscopy were used to study the products of the interaction of vinyl cations C3H5+ and C4H7+ (Cat+) (as salts of carborane anion CHB11Cl11−) with basic molecules of water, alcohols, and acetone that can crystallize from solutions in dichloromethane and C6HF5. Interaction with water, as content increased, proceeded via three-stages. (1) adduct Cat+·OH2 forms in which H2O binds (through the O atom) to the C=C+ bond of the cation with the same strength as seen in the binding to Na in Na(H2O)6+. (2) H+ is transferred from cation Cat+·OH2 to a water molecule forming H3O+ and alcohol molecules (L) having the CH=CHOH entity. The O- atom of alcohols is attached to the H atom of the C=C+-H moiety of Cat+ thereby forming a very strong asymmetric H–bond, (C=)C+-H⋅⋅⋅O. (3) Finally all vinyl cations are converted into alcohol molecule L and H3O+ cations, yielding proton disolvates L-H+-L with a symmetric very strong H-bond. When an acetone molecule (Ac) interacts with Cat+, H+ is transferred to Ac giving rise to a reactive carbene and proton disolvate Ac-H+-Ac. Thus, the alleged high reactivity of vinyl cations seems to be an exaggeration

Interaction of Vinyl-Type Carbocations, C3H5+ and C4H7+ with Molecules of Water, Alcohols, and Acetone

X-ray diffraction analysis and IR spectroscopy were used to study the products of the interaction of vinyl cations C3H5+ and C4H7+ (Cat+) (as salts of carborane anion CHB11Cl11−) with basic molecules of water, alcohols, and acetone that can crystallize from solutions in dichloromethane and C6HF5. Interaction with water, as content increased, proceeded via three-stages. (1) adduct Cat+·OH2 forms in which H2O binds (through the O atom) to the C=C+ bond of the cation with the same strength as seen in the binding to Na in Na(H2O)6+. (2) H+ is transferred from cation Cat+·OH2 to a water molecule forming H3O+ and alcohol molecules (L) having the CH=CHOH entity. The O- atom of alcohols is attached to the H atom of the C=C+-H moiety of Cat+ thereby forming a very strong asymmetric H–bond, (C=)C+-H⋅⋅⋅O. (3) Finally all vinyl cations are converted into alcohol molecule L and H3O+ cations, yielding proton disolvates L-H+-L with a symmetric very strong H-bond. When an acetone molecule (Ac) interacts with Cat+, H+ is transferred to Ac giving rise to a reactive carbene and proton disolvate Ac-H+-Ac. Thus, the alleged high reactivity of vinyl cations seems to be an exaggeration

Взаимодействие 1,3λ⁴δ²,2,4-бензодитиадиазинов с нейтральными и заряженными S-электрофилами:SCl₂, C₆F₅SCl и NS₂⁺

Abstract Reactions of 1,3λ⁴δ²,2,4-benzothiadiazines with SCl₂, C₆F₅SCl, and [NS₂][SbF₆] leading to 1,2,3-benzodithiazolium salts (Herz salts) were investigated. The relative rate of reaction with SCl₂ significantly depends on the nature of the substituent and its position in the carbocycle. Halogen substituents Cl, Br, and I slow down the reaction, especially if located closely to the heterocycle (positions 5 and 8). In the case of C₆F₅SCl and R = H, chlorination of the carbocycle and opening of the heterocycle also takes place with the formation of 7-chloro-1,3λ⁴δ²,2,4-benzothiadiazine аnd C₆F₅–S–N=S=N–Ar (Ar = 2-Cl-6-F₅C₆SC₆H₃), respectively. In the reaction with NS₂⁺, along with contraction of the heterocycle, also its expansion occurs with the formation of 1,2,⁴λ4δ²,3,5-benzotrithiadiazepine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, 2020, 56(7), 968–972. http://hgs.osi.lv/index.php/hgs/article/view/5758Аннотация Изучены реакции 1,3λ⁴δ²,2,4-бензодитиадиазинов с SCl₂, C₆F₅SCl, и [NS₂][SbF₆], приводящие к солям 1,2,3-бензодитиазолия (солям Херца). Относительная скорость реакции с SCl₂ существенно зависит от природы и положения заместителя в карбоцикле. Галогены Cl, Br и I замедляют реакцию, особенно вблизи гетероцикла (в положениях 5 и 8). В случае C₆F₅SCl и R = H происходит также хлорирование карбоцикла и раскрытие гетероцикла с образованием 7-хлор-1,3λ⁴δ²,2,4-бензодитиадиазина и C₆F₅–S–N=S=N–Ar (Ar = 2-Cl-6-F₅C₆SC₆H₃), соответственно. В реакции с NS₂⁺, наряду с сокращением гетероцикла, происходит его расширение с образованием 1,2,⁴λ4δ²,3,5-бензотритиадиазепина

(1S,5R)-6,6-Dimethyl-4-(((1S,2S,5S)-2,6,6-trimethyl-4-oxobicyclo[3.1.1]heptan-2-yl)methyl)bicyclo[3.1.1]hept-3-en-2-one

A simple and convenient procedure for the γ, β-dimerization of verbenone was developed. The dimer was obtained during aging with KOH without a solvent. The process proceeds as the formation of the extended enolate of verbenone and its Michael addition to other molecules of verbenone. The product yield was 82% after purification by column chromatography and recrystallization

Interaction of 1,3,2,4-benzodithiadiazines with aromatic phosphines and phosphites

Although an interaction between hydrocarbon and fluorocarbon 1,3,2,4-benzodithiadiazines (1 ) and P(C6H5)3 continuously produces chiral 1,2,3-benzodithiadiazol-2-yl iminophosporanes (2; in this work, 5,7-difluoro derivative 2a ) via 1:1 condensation, an interaction between 1 and other PR3 reagents gives different products. With R [DOUBLE BOND] OC6H5 and both hydrocarbon and fluorocarbon 1, only X=P(OC6H5)3 (X = S, O) were identified in the complex reaction mixtures by 13С and 31Р NMR and GC-MS. With R = C6F5, no interaction with the archetypal 1 was observed but catalytic addition of atmospheric water to the heterocycle afforded 2-amino-N-sulfinylbenzenesulfenamide (4 ). With electrophilic B(C6F5)3 instead of nucleophilic P(C6F5)3, only adduct H3N→B(C6F5)3 and a new polymorph of C6F5B(OH)2 were isolated and identified by X-ray diffraction (XRD). A molecular structure of 2a was confirmed by XRD, and the π-stacked orientation of one of phenyl groups and heterocyclic moiety was observed. This structure is in general agreement with that calculated at the RI-MP2 level of theory, as well as at three different levels of DFT theory with the PBE and B3LYP functionals. Mild thermolysis of 2a in a dilute decane solution gave persistent 5,7-difluoro-1,2,3-benzodithiazolyl (3a ) identified by EPR in combination with DFT calculations

3,1,2,4-Benzothiaselenadiazine and related heterocycles: synthesis and transformation into Herz-type radicals

The archetypal 3,1,2,4-benzothiaselenadiazine, its 5- and 8-Me3Si derivatives and related dithiadiazine and trithiadiazepine were synthesized from 2-Me3SiC6H4N=S=NSiMe3 by the action of SeCl2, SeCl4, SCl2, and S2Cl2 and converted into persistent 2,1,3-benzothiaselenazolyl and 1,2,3-benzodithiazolyl radicals characterized by EPR spectroscopy and DFT calculations