Synthesis and diels-alder reactions of e-1-trimethylsilylbuta-1,3-diene

A novel synthesis of E-1-trimethylsilylbuta-1,3-diene (1) has been achieved, and its Diels-Alder reactions with maleic anhydride, diethyl maleate, dimethyl fumarate, methyl propiolate, acrolein and acrylonitrile have been investigated. The structures of the products were studied to determine the stereoselectivity and regioselectivity of the reactions of this diene. In all cases with monosubstituted dienophiles the silyldiene 1 afforded the 1,3-disubstituted isomer (meta isomer) as the predominate regioisomer.     

Synthesis of phosphonates immobilized on a polycyclic platform and conjugated with triazole moieties

Russian Chemical Bulletin - Oligofunctionalized 1,1′-methylenedinaphthalenes and rctt-o-methyltetra(C-naphthyl)-resorcincalix[4]arenes, wherein exocyclic substituents contain phosphonate and...     

Mechanism of the reactions of diazaphospholes with diazo compounds

Conclusions Diazaphospholes react with diazo compounds by the mechanism of 1,3-dipolar cycloaddition. The reaction of 2-acetyl-5-methyl-1,2,3-diazaphosphole with diphenyldiazomethane proceeds via the intermediate formation of the product of [2 + 3]-cycloaddition.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1376–1380, June, 1987.     

Palladium-Catalyzed Reaction of 1,3-diene monoepoxides with sodium azide. 1,4-Azidohydroxylation of conjugated dienes.

Palladium-catalyzed regioselective 1,4-addition of sodium azide to vinylepoxides afford 4-azido-2-alkenols in good yields.     

Asymmetric cobalt-catalyzed Diels-Alder reactions of a boron-functionalized 1,3-diene with alkynes and allylboration with aldehydes

[Structure: see text] A cobalt(I)-catalyzed Diels-Alder reaction of a 1-boron-functionalized 1,3-diene is the key step in a one-pot reaction interconnecting three simple starting materials to obtain a multifunctionalized product. This product incorporates a stereogenic quaternary center next to a stereogenic secondary alcohol functionality generated with a very high degree of regio- and diastereoselectivity and good enantioselectivity in the presence of a chiral ligand such as (S,S)-Norphos.     

Synthesis of glycosyl phosphonates and related compounds

The synthesis of glycosylphosphonates, isopolar, nonisosteric analogues of glycosylphosphates, from halonitro ethers, glycosyl acetates, or glycosyl trichloroacetimidates is reviewed. A new approach to phosphonate analogues of myo-inositol trisphosphate ( 50 ) is described. Based on a hypothetical reaction mechanism for the formation of thioethers from a glyoxalase I inhibitor, an advanced intermediate 59 for the synthesis of diphosphonate–phosphate analogues of 50 is obtained by an addition–elimination–addition sequence from 54 . Finally, glucosylphosphines, characterized as the corresponding phosphine oxides 61 and 62 have been prepared from the glycosylidene diazirine 60 , a precursor of the tetra-O-benzylglucopyranosylidene carbene. The phosphine oxides 61 and 62 were also obtained by reaction of the glycosyl acetate 18 with methyl diphenylphosphinite.     

Progress in intermolecular and intramolecular reactions of thioamides with diazo compounds and azides

Reactions of thioamides with nitrogen-rich 1,3-dipoles, diazo compounds and azides, have been known for long time already. However in recent years introduction of catalysts of different types (rhodium-, ruthenium- and copper-containing and Lewis acids) as well as highly electrophilic sulfonyl azides, allowed the development of new methods for the synthesis of heterocycles, enamines and N-sulfonyl amidines. Moreover, a new methodology in organic synthesis, based on generation and subsequent transformations of α-diazocarbonyl compounds was created. Reactions of sulfonyl azides with thioamides undergo readily in mild conditions to produce different sorts of N-sulfonyl amidines and represent a new type of click-type processes. Most of the cited works were published in the current decade. Earlier seminal papers are also reviewed when they constitute the background for new synthetic methods which were developed further.     

Stannoboroxanes : III. Synthesis and reactions of 1,3-bis(boryloxy)tetraalkyldistannoxanes and related compounds

1,3-Bis(boryloxy)tetraalkyldistannoxanes,

, R = Me, Bu; G = CMe₂CH₂CHMe—, —CMe₂ —CMe₂ — and —CHMe—CH₂ — have been prepared from dialkyltin oxide and pyroborate, or directly from dialkyltin oxide, boric acid and glycol. A dimeric structure for these compounds is proposed on the basis of molecular weight, IR and PMR studies. The reactivity of the SnOB bond towards PhNCO and Me₃SiCl has been demonstrated.     

有机磷化合物研究XVIII α-砜基膦酸酯的合成和反应

本文报道α-砜基碳阴离子和磷酰氯的反应,提供了合成α-砜基膦酸酯和α,β-不饱和砜的新方法,此方法具有原料易得、反应步骤少、得率较高等优点.还讨论了α-芳砜基膦酸酯的质谱.     

Synthesis of conjugated (E,E)-1,3-diene-containing troponoid-based compounds

Through exploration of the electrophilic substitution reaction of 3-((2E,4E)-5-phenylpenta-2,4-dienoyl)-2-hydroxy-2,4,6-cycloheptatrien-1-one (3-((2E,4E)-5-phenylpenta-2,4-dienoyl)tropolone) with halogen and diazonium salts as well as the nucleophilic cyclisation reaction with hydroxylamine hydrochloride and substituted phenylhydrazine hydrochlorides by employing our reliable methods, we have synthesised a series of new (E,E)-1,3-diene-bearing troponoid-based compounds. All the newly synthesised molecules represent an issue of great interest, since the presence of conjugated 1,3-diene moiety can be developed further via other reactions.     

Photochemical reactions. 142nd communication. Photochemistry of a 6,7-epoxy-1,3-diene of the ionone series

On singlet excitation (λ = 254 nm), the epoxydiene (E)- 3 underwent (E)/(Z)-isomerization, electrocyclic ring closure of the diene side chain leading to the cyclobutenes 4A + B , and rearrangement to the cyclohexanones 5A + B . Compounds 5A + B were presumably formed in a series of processes including a 1,3-acyl shift of the homoconjugated ketone 8 , arising from (Z)- 3 by a 1,5-H-shift accompanied by cleavage of the C,O-bond of the oxirane.     

Chemistry of diazocarbonyl compounds: XXV. Comparative photochemistry of diazo compounds and sulfur ylides of the 1,3-dioxane-4,6-dione series

Photochemical decomposition of 2,2-dialkyl-5-diazo-1,3-dioxane-4,6-diones in the presence of pyridine, methanol, or dimethyl sulfide as carbene traps involves mainly the Wolff rearrangement which is likely to follow a concerted pattern, while the yield of the “carbene” products does not exceed 27–28%. No carbene intermediates are formed in the photolysis of the corresponding dioxo sulfonium ylides under analogous conditions, and the main photochemical process is 1,2-methyl shift (Stevens rearrangement), followed by photochemical transformations of the primary products according to the Norrish type II pattern.     

Perfluoroacetylenephosphonates in Diels-Alder reactions: Synthesis of perfluoroalkylated heterocyclic and carbocyclic phosphonates

Diethyl 3,3,3-trifluoroprop-1-ynylphosphonate and diethyl 3,3,4,4,4-pentafluorobut-1-ynylphosphonate are obtained by the dehydration of the corresponding enols using P₂O₅-Et₃N system as a dehydrating agent, affording acetylenes in 50-60% yield. By the reaction of these perfluoroacetylenephosphonates with acyclic and cyclic 1,3-dienes or diene-like heteroaromatic and aromatic compounds corresponding Diels-Alder cyclo- and bicycloadducts were prepared in good yields (65-90%). The reactivity of the dienes and acetylenes which depends on their structure, as well as the regioselectivity of the reaction are established.     

Polymerization of penta-1,3-diene using cationic catalytic systems based on organoaluminum compounds

Russian Chemical Bulletin - Cationic polymerization of penta-1,3-diene with catalytic systems based on organoaluminum compounds (AlEtCl2, AlEt2Cl, and AlEt3) in combination with isopropyl chloride...