Carbonylation Reactions of a Metallapentalyne:Synthesis of Its Ester and Amide Derivatives

omprehensive Summary Carbonylation reactions are a valuable synthetic method to construct carbonyl compounds and carbonylation reactions of aryl halides stand out as a highly significant tool for generating carbonyl substituted arenes.However,the important reactions have never been realized in aromatic metallacycles.Herein,we present the first carbonylation reactions of metallaaromatics,specifically alkoxycarbonylation and aminocarbonylation reactions of an osmapentalyne.During the carbonylation process,the electronic and steric properties of nucleophiles are regarded as critical factors.The alcohols with bulky substituents(isopropanol)require more reaction time and tert-butyl alcohol is inert in the reaction.Comparatively,amines,being stronger nucleophiles,exhibit divergent behaviors.Bulky amines undergo aminocarbonylation,whereas small amines prefer direct nucleophilic additions.Control experiments revealed that the intermediate derived from coupling of metal carbyne with CO plays a significant role in the carbonylation reaction.According to these observations,a divergent pathway for the reaction is proposed.Furthermore,the photophysical properties of these carbonyl-functionalized osmapentalene complexes are studied,and the maximum absorption peak of compound with a carboxylic group exhibits a significant red-shift due to the smaller HOMO-LUMO gap.These findings contribute to expanding the reactivity of metallaaromatics and offer new opportunities for the synthesis of carbonyl-functionalized metallacycles.

Development of palladium-catalyzed Suzuki carbonylation reaction without external ligand and its application in modification of novel series of α7 nAChR PAMs

Palladium-catalyzed Suzuki carbonylation with CHCl3 as carbonylative reagent was realized without external ligands. Different substituted benzophenones were explored via the coupling reaction of aryl iodides, arylboronic acids and CHCl3 as a CO surrogate in moderate to good yields. This method was also successfully applied to the structure modification of α7 nicotinic acetylcholine receptor positive allosteric modulators（α7 nAChR PAMs） based on the preliminary structure-activity relationship.

Ionic palladium complex as an efficient and recyclable catalyst for the carbonylative Sonogashira reaction

The neutral palladium（Ⅱ） complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-imidazolyl]dichloropalladium（Ⅱ）（1A） ligated by thiazolylimidazolyl-based phosphine（L1） in which thiazolylimidazolyl acted as an S- and N-donor provider with weak coordinating nature,and the ionic complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-3-methylimidazolium]dichloropalladium（Ⅱ） trifluoromethanesulfonate（2A） ligated by thiazolylimidazolium-based phosphine（L2） after quaternization of L1 using methyl trifluoromethanesulphonate were synthesized.It was found that the introduced positive charges and strong electron-withdrawing effect in 2A not only led to changes in the configuration and structural stability of the complex,but also lowered its catalytic performance in carbonylative Sonogashira reactions.These effects reveal the important role of the N-donor in 1A.In addition,as an ionic palladium complex,2A combined with the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate could be recycled eight times as the catalyst in carbonylative Sonogashira reactions without detectable metal leaching.

Zeolite-Catalyzed Acetalization Ⅰ. Synthesis of Some Acetals and Ketals through Reaction of Carbonyl Compounds with Ethanediol

The acetalization of a series of carbonyl compounds with ethanediolwas performed over two self-steaxned HY zeolle catalpsts' The acetal and ketaiproducts were obtained with high ytelds Espectw, the HY zeollte with highfraxnework Si/A1 ratio was proven to be suitable cataipst for the acetabotion ofunsaturated carbonyl compounds, during which the C =C double bond was notperturbed

Palladium-catalyzed 3,4-hydroaminocarbonylation of conjugated dienes for formation ofβ,γ-unsaturated amides

Hydrocarbonylation of conjugated dienes is one of the most promising yet challenging methods for the synthesis of carbonyl compounds.Herein,we reported the development of an unprecedented palladium-catalyzed branched selective 3,4-hydroaminocarbonylation of 1,3-dienes with CO and amines hydrochloride to affordβ,γ-unsaturated amides.This reaction employs readily available starting materials(including anilines,amines,amino acids,peptides,aryl-1,3-dienes,alyl-1,3-dienes)and tolerates a wide range of functional groups,thus providing a facile and effective approach to access a diverse array ofα-substitutedβ,γ-unsaturated amides.Mechanistic investigations suggested that the hydropalladation of dienes is irreversible,and the insertion of CO into the allyl-Pd species is probably the rate-limiting step.

Regioselective synthesis of linalyl compounds via addition reaction of geranyl bromide and tin with carbonyl compounds

Linalyl alkyl or aryl carbinols were regioselectively synthesized by the reaction of geranyl bromide and powdered tin with aldehydes and ketones.

Facile synthesis of isoindoline-l,3-diones by palladium-catalyzed carbonylative cyclization of o-bromobenzoic acid and primary amines

A facile method for the carbonylative cycliza- tion of o-bromobenzoic acid with primary amine using Pd（OAC）2 as a metal precursor and 1, l′-bis（diphenylpho- sphino）ferrocene （dppf） as a ligand has been developed. The effect of various reaction parameters such as ligand, solvent, base, time and temperature on this cyclization was studied. The optimized protocol was used for a wide variety of substituted aryl amines with different steric and electronic properties, affording the corresponding isoindoline-l,3-diones in good to excellent yields under atmospheric pressure of carbon monoxide at 100℃ within 10h using 1,4-diazabicyclo[2.2.2]octane （DABCO） as a base. The reaction system finds attractive alternative to the conventional multistep synthetic process and thus repre- sents an effective utilization of carbonylative protocol for synthesis of valuable chemicals.