Synthesis of α-aryl-diazophosphonates via palladium-catalyzed cross-coupling of aryl iodides with diethyl diazomethylphosphonate

An efficient procedure for the Pd-catalyzed arylation of diethyl α-diazomethylphosphonate with aryl iodides is described. It can serve as a pathway for the generation of arylated diazophosphonates, which are typically difficult to access. The significance of this methodology was demonstrated via further synthetic transformations of newly synthesized diazo compounds in cyclopropanation, epoxidation, N–H and O–H insertion reactions.     

Kinetic Study on Models of the Noncatalyzed Reaction Between α, ω -Dicarboxypolyamide-11 and α, ω -Dihydroxypolyoxyalkylenes

The kinetics of the noncatalyzed reaction between α, ω -dicarboxypoly-amide-11 and α, ω -dihydroxypolyoxyalkylenes is investigated by using the reactions of 11-dodecylamidoundecanoic acid with 1-dodecanol, 2-tridecanol, α-dodecyl-ω-hydroxypolyoxyethylene or α-dodecyl-ω;-hydroxypolyoxypropylene as models. Kinetic data fit a 3rd overall order (2 in acid and 1 in alcohol). Rate constants and activation parameters are determined and compared.     

Kinetic Study on Models of the Tetrabutqxyzirconium-Catalyzed Reaction Between α, ω -Dicarboxypolyamide-11 and α, ω -Dihydroxypolyoxyethylene

The kinetics of the tetrabutoxyzirconium-catalyzed esterifications between 11-dodecylamideundecanoic acid and 1-dodecanol, 2-tridecanol, a-dodecyl-ω-hydroxypolyoxyethylene are studied and compared to that of α, ω-dicarboxypolyamide-l 1 and α, ω-dihydroxypolyoxyethylene. The reaction with 2-tridecanol is characterized by an autoacceleration phenomenon. In the other cases the reaction rate is not greatly affected by catalyst concentration. An explanation involving the formation of catalyst condensates at the very beginning of the reaction is put forward.     

Synthesis and Properties of Long-Chain Aromatic Telechelic Monodispersed Diols Radical-Initiated,Addition of 2-Mercaptoethanol onto α, ω Nonconjugated Dienes

Abstract

The synthesis of aromatic telechelic mono dispersed diols produced from the radical-initiated addition reaction of a twofold excess of 2-mercaptoethanol onto original α,ω nonconjugated dienes reaction is presented. These novel α,ω nonconjugated dienes were prepared by addition reaction of m-isopropyl α,α′dimethyl benzylisocyanate with mono dispersed telechelic diols obtained by fractionation of oligo(ethylene terephthalate)s. In these cases, the long chain α,ω diols were produced selectively and quantitatively. The products are soluble in most organic solvents in contrast to classical oligo (ethylene terephthlate)s and posses a lower glass transition and melting temperatures.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Figures S1-S3.     

Synthesis of α-Diketones from α,β-Dihydroxy Ketones

Treatment of α,β-dihydroxy ketones with carbonyldiimidazole resulted in the formation of α-diketones based on the elimination of the cyclic carbonates formed in situ.     

Palladium-catalyzed reductive Heck reaction of α,β-unsaturated alkenes and cycloalkyl iodides

The palladium catalyzed reductive Heck reactions of unactivated cycloalkyl iodides with α,β-unsaturated alkenes have been developed. A number of hydrocycloalkylated alkenes were obtained in reasonable yields under the optimized conditions. The obvious advantage of this approach is that the hydride source was provided by Et₃N and no other reductant or base was required in the reaction.     

Synthesis of α-oxazolinylalkanamides

The synthesis of α-oxazolinylalkanamides 2, based on the reaction of α-chloroalkyloxazolines 1 with hexacarbonyltungsten [W(CO)₆] and lithium amides, has been developed. A plausible mechanism involving the ketene 5 as the intermediate is also proposed.     

Synthesis of α-alkylthioacroleins

Monomeric -alkylthioacroleins were obtained by the reaction of alkylthioacetaldehydes with formaldehyde and diethylamine hydrochloride. The structures of the -alkylthioacroleins were confirmed by NMR spectroscopy and mass spectrometry as well as by chemical transformations of these compounds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 188–190, January, 1996.     

Synthesis of α-Telluroketones

α-Telluroketones were prepared by reacting 4-methoxyphenyltellurium trichloride either with ketones or silyl enol ethers of ketones. The products upon pirolysis furnish α-chloro ketones.     

Synthesis of α-hydroxyacetophenones

A general method for the preparation of α-hydroxyacetophenones is presented. Functionalized arylmagnesium species are transmetalated to the corresponding arylzinc intermediates, which undergo Cu(I)-catalyzed reaction with acetoxyacetyl chloride. Acidic hydrolysis of the acetate group releases the target α-hydroxyacetophenones with minimal production of undesired polymeric degradates that are often observed under alternative conditions.     

Synthesis and characterization of α,ω-dichloro-polymethylphenylsilane

The synthesis of a functional polysilane, α,ω-dichloro-polymethylphenylsilane (α,ω-dichloro-PMPS), based on the Wurtz-type reductive coupling, has been considered. A study of some reaction parameters shows that both yield and molecular weight distribution of α,ω-dichloro-PMPS can be greatly influenced by the work-up conditions, reaction time, monomer concentration and temperature during the initiation of the polymerization. By varying the synthesis conditions, different ratios of high and low molecular weight fractions were obtained. Samples of different molecular weight were isolated by fractional precipitation of the crude polymers. The chlorine-end functionalization was confirmed by ²⁹Si NMR spectroscopy and the concentration of end-groups was quantitatively determined by elemental analysis of chlorine.     

Synthesis of α-alkyl- and α,α-dialkyl-β-phenyltryptamines

A new method was developed for the synthesis of -alkyl- and ,-dialkyl--phenyltryptamines based on alkylation of nitroalkanes with -phenyl-nor-gramine.     

One Step Synthesis of α-Substituted α, β-Unsaturated Aldehydes

Abstract

The conversion of carbonyl compounds into cmologated α, β-unsaturated aldehydes (“formylolefination”) is a highly useful transformation in organic synthesis. A large number of methods have been reported for effecting such a chain lengthening. These proceed mainly via silylated intermediates or via phosphorylated reagents. The “phosphonate-strategy” has found widespread use, but leads exclusively to α,β-unsaturated aldehyess, non-substituted in the α-position.     

Synthesis of New α-Heterocyclic α-Aminophosphonates

α-heterocyclic α-aminophosphonates were obtained in good yields by N-of several nitrogen heterocycles with α-azido-α-aminophosphonate 1. ¹ Elachqar, A., El Hallaoui, A., Roumestant, M. L. and Viallefont, Ph. 1994. Synthetic Comm, 24: 1279 [CSA][Taylor & Francis Online], [Web of Science ®] , [Google Scholar]     

Synthesis,Characterization, and Structures of α-Substituted Selenenyl-Acetophenones

Abstract

A series of α-substituted selenenyl acetophenone derivatives of the types, [PhC(OCH₂CH₂O)CH₂Se]₂, [PhC(OCH₂CH₂O)CH₂SeR], (PhCOCH₂Se)_2, and [PhCOCH₂SeR] have been prepared. These compounds have been characterized by elemental analyses, IR and NMR (¹H, ¹³C, ⁷⁷Se) spectroscopy. The compounds, [PhC(OCH₂CH₂)CH₂Se]₂ and (PhCOCH₂Se)₂ have been structurally characterized by single crystal X-ray diffraction analyses. The former shows intra-molecular Se‐?‐?‐O interaction, while the latter exhibits inter-molecular nonbonding Se‐?‐?‐O interaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Synthesis of New Tetrazole Derivatives of α,α‐Trehalose

Five new nitrogen heterocycles, mono‐and disubstituted tetrazoles with potential synthetic and pharmacological interest, were synthesized from α, α‐trehalose via the alkylation of commercial tetrazoles. This method appears to have broad scope with respect to the variations at positions 1 and 2 of tetrazole.