Rhodium(Ⅲ)-catalyzed selective access to isoindolinones via formal [4+1] annulation of arylamides and propargyl alcohols

A mild and efficient oxidative synthesis of isoindolinones has been realized by Rh(III)‐catalyzed C?H activation of benzamides and[4+1]coupling with propargyl alcohols.This coupling system proceeds with broad substrate scope and mild conditions and provides a new approach to access the useful skeleton ofγ‐lactams with a stereogenic center.

Synthesis of α-hydroxy ketones by copper（Ⅰ）-catalyzed hydration of propargylic alcohols: CO2 as a cocatalyst under atmospheric pressure

Inexpensive and efficient Cu(Ⅰ) catalysis is reported for the synthesis of α-hydroxy ketones from propargylic alcohols, CO2, and water via tandem carboxylative cyclization and nucleophilic addition reaction. Notably, hydration of propargylic alcohols can be carried out smoothly under atmospheric CO2 pressure, generating a series of α-hydroxy ketones efficiently and selectively. This strategy shows great potential for the preparation of valuable α-hydroxy ketones by using CO2 as a crucial cocatalyst under mild conditions.

Facile synthesis of bromoallenes via N-bromosuccinimide/CH_3SCH_3 for the bromination of propargyl alcohols

A novel and convenient way has been developed for the preparation of bromoallenes from propargyl alcohols by the reagent combination of N-bromosuccinimide and dimethyl sulfide. Bromoallenes with high regioselectivity were obtained in a convenient method.

Practical synthesis allenyl and homopropargyl alcohol through Cp_2TiCl_2 -Mg with propargyl alcohol derivatives

Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synthesis of both allenyl and homopropargyl alcohols by the successive treatment with aldehydes and ketones.

A Novel Thin Film Resistive Humidity Sensor Based on SolubleConjugated Polymer:(propionic acid)-co-(propargyl alcohol)

A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)(2)(C=CC(CH3)(2)OH)(2)(PPB). Thin film resistive humidity sensor based oil the copolymer doped with HClO4 was prepared. The impedance of the sensor changed from 10(3)similar to 10(7) Omega in 95%similar to 30%RH, and the response of that is very quick (<6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.

Cu(OTf)_(2) Catalyzed Rapid Nucleophilic Substitution of Propargyl Alcohols

The propargylation of various nucleophiles including indoles,phenol,anisole,enoxysilanes,and alcohols was rapidly achieved using catalytic copper(Ⅱ)triflate.The reaction conditions are mild,allowing for quick reactions in an undried solvent and under atmospheric air.The desired products are obtained with good yields.

CuCl-Catalyzed Aerobic Oxidation of Allylic and Propargylic Alcohols to Aldehydes or Ketones with 1 ： 1 Combination of Phenanthroline and Bipyridine as the Ligandst

We developed a modified protocol for the oxidation of 2,3-allenyl alcohols using CuCI with l ： 1 combination of phenanthroline and bipyridine as the catalyst. To further investigate the applicability of this system, other types of alcohols such as allylic and propargylic alcohols have been tested： we found that both allylic and propargylic alcohols may be oxidized to the corresponding aldehydes or ketones using molecular oxygen in air as the oxidant with moderate to excellent yields.

Enantioselective Addition of Phenylacetylene to Ketones Catalyzed by Titanium（IV） Complexes of N-Sulfonylated β-Amino Alcohols

The easily prepared and recoverable chiral N-sulfonylated fl-amino alcohol 2 in combination with Ti（OPr-i）4 was found to be an effective chiral catalyst for the enantioselective addition of alkynylzinc to ketones, which gave the useful products, i.e. chiral tertiary propargyl alcohols, with the ee up to 92%.

Co_(2)(CO)_(8)-mediated Selective Reductions of Propargyl Alcohol Derivatives to Alkenes

In the presence of Co_(2)(CO)_(8) and additives,propargyl alcohol derivatives could be reduced to alkenes in moderate to good yield.The selectivity of this reaction could be controlled by adding different additives:with H_(2)O as the additive,the major configuration of product is Z-alkene;with CF_(3)COOH as the additive,the major configuration of product is E-alkene.

Preparation of phenyl substituted propargylic alcohol dicobalt hexacarbonyls and their reactions with active methylene compounds in the presence of acid

Eight new complexes with the formula [PhC_2C(OH)R^2R^2]Co_2(CO)_6 were prepared from phenyl substituted propargylic alcohols and dicobalt octacarbonyl.The reactions of these propargylio alcohol complexes with active methylene compounds,2,4-pentanedione or ethyl acetoacetate,in the presnce of an acid,HBF_4(40％)+P_2O_5(in excess)or BF_3·Et_2O,at room temperature in dichlorome- thane were investigated.From the 1-alkyl substituted tertiary propargylic alcohol complexes,three new conjugated ene-yne complexes produced by intramolecular dehydration reaction were isolated in high yields(82—95％).On the other hand,four new alkylated complexes were obtained with satisfactory yields(44—66％)from the secondary propargylic alcohol complexes.The influence of other acids,phosphorus pentoxide and polyphosphoric acid,on both dehydration reaction and alkylated reaction was also studied.

Synthesis of Cyclic Carbonates from Alkenyl and Alkynyl Substrates

As an extensively used chemical product,cyclic carbonate was generally synthesized by transesterification,or the cycloaddition of epoxides,diols with CO2.To reduce the production costs and expand the raw materials,alkenyl and alkynyl substrates have caused much attention in the synthesis of cyclic carbonates,such as olefins,allyl alcohols and propargylic alcohols.Based on the alkenyl substrate,the synthetic process involves a continuous reaction of oxidative carboxylation,with epoxide or halohydrin as an intermediate usually.Therefore,peroxides and nucleophiles （halogens or organic bases） are often necessary in the conversion.Using propargylic alcohols to produce a-alkylidene cyclic carbonates,noble metal catalysts play crucial roles in alkynyl activation,and organic bases are considered to assist the intramolecular and intermolecular proton transfer and combine CO2 molecular.As the carboxyl sources in products,inorganic carbonates and organic carboxylic acids also have some applications instead of CO2.In this review,we summarized the synthetic routes of cyclic carbonates from alkenyl and alkynyl substrates in the aspect of catalyst,mechanism and the development tendency.

The Lewis Acid-promoted Novel Cyclization Reactions Towards N-adn O-Containing Heterocycles

1 Results Nitrogen and oxygen-containing heterocyclic systems are important structures in organic chemistry because of their presence in many biologically active compounds.In this work,a new zinc and indium-promoted conjugate addition-cyclization reaction to afford nitrogen and oxygen-containing five-membered heterocycles has been developed.A Lewis acid-catalyzed cyclization of an ethenetricarboxylate derivative with propargylamines or propargyl alcohols to give methylenepyrrolidines and methylenetetrah...