Quantum Chemical Study of the Addition of Secondary Phosphine Chalcogenides to Vinyl Selenides

Russian Journal of Organic Chemistry - DFT quantum chemical calculations at the B3PW91/6-31G(d) level of theory have shown that the addition of secondary phosphine sulfides and phosphine selenides...     

Self-Catalytic Michael Reaction,An Efficient Route to 2-Cyanoalkanoic Acids

The self -- catalytic Michael reaction of several 1,3-dicarbonyl compounds with dicyclohexylammonium 2-cyanoacrylate proceeded highly efficiently at room temperature to give the corresponding 1,4-adducts.     

FeCl3-Mediated Reaction of Alkynols with Iodine: An Efficient and Convenient Synthetic Route to Vinyl Iodides

The FeCl₃-mediated reaction of alkynols with iodine resulted in intramolecular addition of hydroxyl to alkyne to produce a wide range of iodocycloenol ethers in good to excellent yields under mild reaction conditions. On the other hand, 1,2-diiodides were obtained in good yields when propargyl alcohol reacted with iodine in the same condition.

Diastereoselective Ruthenium-Catalyzed Michael Addition of Indoles to Hormone Steroids: An Efficient Route to New Indole Derivatives

Diastereoselective conjugate 1,4-addition of indoles to α,β-unsaturated carbonyl compounds (hormone steroids) using Ru(III) as catalyst is reported. It was found that RuCl₃·nH₂O catalyzes the Michael addition of indoles to hormone steroids, providing new 3-alkylated derivatives in good to excellent yields.     

An Alkyl-Aluminium Promoted Stereospecific Addition to Vinyl Olefins

The reaction of tris-crotyl-boron with vinylic olefins in the presence of triethyl-aluminium, results in the addition of an α-methylallyl group and an aluminium atom to the double bond, as indicated by the hydrolysis products. The stereochemical aspect of the reaction is discussed and a mechanism is proposed to explain the preferential formation of one diastereoisomer.     

A General and Efficient Route for the Preparation of Phenyl-Substituted Vinyl Fluorides

α-Fluorobenzyl phosphonate (EtO)₂P(O)CFHPh ( 2 ) prepared from diethyl α-hydroxyphosphonate (EtO)₂P(O)CH(OH)Ph ( 1 ) and diethylaminosulfur trifluoride (DAST), reacts with bases such as butyllithium, tert-butyllithium, lithium bis(trimethylsilyl)amide, or lithium diisopropylamide at −78° in THF to give the phosphonate carbanion [(EtO)₂P(O)CFPh]⁻Li⁺ ( 3 ) which was detected by acylation with propionyl chloride or by addition of MeOD to the reaction mixture to give (EtO)₂P(O)CF(COEt)Ph ( 4 ) and (EtO)₂P(O)CFDPh ( 5 ), respectively. Addition of aldehydes or ketones to a THF solution of carbanion 3 led to moderate-to-good yields of phenyl-substituted vinyl fluorides RR′C=CFPh 6 . The stereoselectivity of the products PhCH=CFPh ( 6a ) and Ph(Me)C=CFPh ( 6i ) formed in the reaction was examined. The presence of hexamethylphosphoric triamide or N,N′-dimethylpropyleneurea as cosolvent in the preparation of 6a and 6i increased the (Z)-stereoselectivity. However, the presence of LiCl in THF did not alter the (E)/(Z)-ratio of the product.     

锡促进的烯丙基硒醚和烯丙基硫醚的合成

在金属锡促进下，烯丙基溴与二硒醚或二硫醚反应，生成烯丙基硒醚或烯丙基硫醚 。     

Preparations and Polymerizations of p-Substituted Phenyl Vinyl Sulfides. Vinyl Polymerization 168

Abstract

p-Substituted phenyl vinyl sulfides (PVS) were prepared and their radical polymerizations were investigated dilatometrically to determine some kinetic constants and to deduce the influences of the sulfur atom and p-substituents of PVS. It was found that PVS could be easily homopolymerized by ordinary radical polymerization mechanisms in the presence of 2,2′-azobisisobutyronitrile, contrary to the case of phenyl vinyl ethers, which do not homopolymerize.

From the rates of polymerization (R_p H) of PVS and those of p-substituted PVS (R_p X) under the same conditions, the plot of log (R_p H/R_p X) against the Hammett's equation was found to give a parabola curve. When these results were plotted by the modified Hammett's equation [log (k_p X/k_p H) = ρσ + γE_R ], however, a straight line with γ = ?4.5 and ρ = 0.35 was obtained. From these results it was concluded that the 3d orbital resonance was important in the transition state of the polymerization of these monomers.     

An Easy Route to (Hetero)arylboronic Acids

An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.     

Synthesis of Polyethylene Containing Allene Groups: A Simple and Efficient Route to Functional Polyethylene

Allene groups are first employed as the reactive moiety in the simple and efficient synthesis of well‐defined functional polyethylene. By copolymerization of ethylene with allene group substituted norbornene, the allene group is successfully introduced into the polyethylene with a high content. The retained allene groups are demonstrated to be highly reactive in following photoinduced functionalized reactions and can be efficiently converted into the functional groups without the multi‐step, time consuming processes that have generally been required in previous reports, providing the side group‐functionalized polyethylene with a wide range of functional group content.     

Functional Methacryloyloxy Acetals: V. Electrophilic Addition of Carboxylic Acids to 2-Vinyloxyethyl Methacrylate

Mono- and dicarboxylic acids (acetic, methacrylic, E-crotonic, and malonic) quantitatively add to 2-vinyloxyethyl methacrylate under mild conditions (1 wt % CF₃COOH, 20–60°C, 1–4 h) according to the Markownikoff rule to give the corresponding mono- and bis-adducts with high regio- and chemoselectivity. The products may be regarded as a new family of functionalized methacrylates.     

A Mild and Regioselective Route to Functionalized Quinazolines

A Rh‐catalyzed ortho‐amidation cyclocondensation sequence gave a range of 4‐aminoquinazolines in high yield. The method features a remarkably mild C(sp²)?H activation step and can be exploited to rapidly access compounds with established biological activity.     

Regioselective Addition of Grignard Reagents to Substituted Tropones

Methyl magnesium bromide has been reacted with a variety of substituted tropones to establish addition regioselectivity patterns. High levels of selectivity were observed in each case examined, and the resultant dihydrotropones were easily converted into highly substituted cycloheptatrienes.     

Microwave‐Assisted Aqueous Reactions: An Efficient Route to Benzodiazepines

Microwave‐assisted three‐ component reaction has been established for the synthesis of benzodiazepines. This reaction promoted by HOAc was conducted by using readily available and inexpensive starting materials in water under microwave irradiation. The present green synthesis shows fascinating characteristics such as the use of water as the reaction solution, concise one‐pot conditions, short reaction periods, easy purification, and reduced waste production without the use of any strong acids or metal promoters.     

Selenium Dihalides Click Chemistry: Highly Efficient Stereoselective Addition to Alkynes and Evaluation of Glutathione Peroxidase-Like Activity of Bis(E-2-halovinyl) Selenides

Highly efficient stereoselective syntheses of novel bis(E-2-chlorovinyl) selenides and bis(E-2-bromovinyl) selenides in quantitative yields by reactions of selenium dichloride and dibromide with alkynes were developed. The reactions proceeded at room temperature as anti-addition giving products exclusively with (E)-stereochemistry. The glutathione peroxidase-like activity of the obtained products was estimated and compounds with high activity were found. The influence of substituents in the products on their glutathione peroxidase-like activity was discussed.     

An Efficient and Mild Preparation of Vinyl Diazo Carbonyl Compounds

The combination of (CF3CO)2O/Et3N is found to be a mild and efficient dehydration condition for β-hydroxy-α-diazo compounds.