Formation and Reactions of Novel Arylsulfido-Bridged Cyclic Organolead Compounds

Desulfurization of tetrathiaplumbolane 2 at 50 °C with three equivalent of triphenylphosphine afforded stable aryl(arylthio)-plumbylene and dithiadiplumbetane. The formation of these products is most likely interpreted in terms of generation of a novel arylsulfido bridged cyclic organolead compounds.     

Difluoromethylation of Heterocyclic Compounds Containing an N=C-C Ambident Nucleophilic System

New fluorine-containing anionic dyes were obtained by reactions of chlorodifluoromethane in alkaline medium with heterocyclic compounds possessing an N=C-C ambident nucleophilic system.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 437–440.Original Russian Text Copyright © 2005 by Petko, Sokolenko, Yagupol’skii.Dedicated to Full Member of the Russian Academy of Sciences V.I. Minkin on his 70th Anniversary     

Selective Reactions with Organoaluminum Compounds

With the aid of selected examples an overview is given of the development trends in highly discriminative reactions using organoaluminum compounds. (1) Isomerization of substituted oxiranes into allyl alcohols has been effected both stereo- and regioselectively by means of a new organoaluminum reagent, diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP); this reaction which provides a new route for the regiospecific transformation of allyl alcohols into 1,3-dienes. (2) A novel nonenzymic heterolysis of allylic phosphates of terpenoids has been effected by organoaluminum compounds and has enabled development of a new method for the selective synthesis of cyclic terpenes. (3) The reductive condensation of α-haloketones with carbonyl compounds in the presence of diethylaluminum chloride and zinc affords β-hydroxy-carbonyl derivatives in good yields with exclusion of undesired self-condensations products.     

双核有机金属化合物的光化学反应

总结了双核金属－金属成键的有机金属化合物的光化学反应,包括光诱导金属－金属键的断裂、配体的离解与取代、光学化学持入反诮、光诱导异构化反应、歧化反应等。     

Reactions of Enaminones with Diazocarbonyl Compounds

The [Cu(acac)₂]‐catalyzed reactions of several tertiary enaminones with three diazocarbonyl compounds, i.e., dimethyl diazomalonate, ethyl diazoacetoacetate, and ethyl diazoacetate, yielded amino‐ and additionally carbonyl‐substituted dihydrofurans, together with further furan derivatives. Due to the conjugation of α‐carbonyl/α‐Ph groups, reactions proceeded only via 1,5‐electrocyclization of corresponding keto‐ylides. On the other hand, in the absence of any α‐substituent, tertiary enaminone and ethyl diazoacetate, reacted via an accompanying mechanism by a push‐pull cyclopropane intermediate, to yield a 2,4‐dicarbonyl‐substituted furan in one step with moderate yield.     

有机固体化合物无溶剂反应

介绍近年来化学家发现的有机固体化合物无溶剂反应的种类及其特点,列举几类无溶剂有机合成反应。     

Tri-n-butylphosphine-Catalyzed Phosphonoethylation Reactions of Hydrophosphoryl Compounds

Russian Journal of General Chemistry - An efficient method for the synthesis of 1,2-bisphosphoryl compounds based on the addition of hydrophosphoryl derivatives to O,O-diethyl vinylphosphonate was...     

Reactions of Phosphorus-Phosphorus Bonded Mixed-Valence Diphosphorus Compounds

Abstract

A novel type of mixed valence diphosphorus compound, involving the grouping Cl-P(-)-P(+)-NEt₂, with the two phosphorus atoms doubly bridged by N.N'-dimethylurea, has become readily available. Reactions of this type of compound have furnished a variety of new structural elements, involving two directly bonded phosphorus atoms in two different oxidation states and / or coordination numbers.     

Ambident reactivities of pyridone anions

The kinetics of the reactions of the ambident 2- and 4-pyridone anions with benzhydrylium ions (diarylcarbenium ions) and structurally related Michael acceptors have been studied in DMSO, CH(3)CN, and water. No significant changes of the rate constants were found when the counterion was varied (Li(+), K(+), NBu(4)(+)) or the solvent was changed from DMSO to CH(3)CN, whereas a large decrease of nucleophilicity was observed in aqueous solution. The second-order rate constants (log k(2)) correlated linearly with the electrophilicity parameters E of the electrophiles according to the correlation log k(2) = s(N + E) (Angew. Chem., Int. Ed. Engl. 1994, 33, 938-957), allowing us to determine the nucleophilicity parameters N and s for the pyridone anions. The reactions of the 2- and 4-pyridone anions with stabilized amino-substituted benzhydrylium ions and Michael acceptors are reversible and yield the thermodynamically more stable N-substituted pyridones exclusively. In contrast, highly reactive benzhydrylium ions (4,4'-dimethylbenzhydrylium ion), which react with diffusion control, give mixtures arising from N- and O-attack with the 2-pyridone anion and only O-substituted products with the 4-pyridone anion. For some reactions, rate and equilibrium constants were determined in DMSO, which showed that the 2-pyridone anion is a 2-4 times stronger nucleophile, but a 100 times stronger Lewis base than the 4-pyridone anion. Quantum chemical calculations at MP2/6-311+G(2d,p) level of theory showed that N-attack is thermodynamically favored over O-attack, but the attack at oxygen is intrinsically favored. Marcus theory was employed to develop a consistent scheme which rationalizes the manifold of regioselectivities previously reported for the reactions of these anions with electrophiles. In particular, Kornblum's rationalization of the silver ion effect, one of the main pillars of the hard and soft acid/base concept of ambident reactivity, has been revised. Ag(+) does not reverse the regioselectivity of the attack at the 2-pyridone anion by increasing the positive charge of the electrophile but by blocking the nitrogen atom of the 2-pyridone anion.     

Reactions of Electron-Rich Olefins with Proton-Active Compounds

Abstract: From the reaction of electron-rich olefins, bis(1,3-dimethylbenzimidazolidine-2-ylidene), I, or bis(3-methylbenzothiazolidine-2-ylidene), II with proton active compounds, such as dimethyl phosphite, diethyl phosphite, acetonitrile and benzaldehyde were obtained 2-substituted benzimidazole or benzothiazole derivatives. The compounds synthesized were identified by ¹H, ¹³ C, ³¹P-NMR, mass, FT-IR spectroscopic techniques and micro analysis.