10.1246/bcsj.68.950
The research investigates the rhodium(I)- and palladium(0)-catalyzed carbonylation of triarylbismuthines with carbon monoxide (CO). The purpose of this study was to explore the conversion of triarylbismuthines into diaryl ketones and methyl benzoates under atmospheric pressure of CO at room temperature, with the key step being the oxidative addition of a carbon-bismuth bond to rhodium(I) and palladium(0). The researchers used various rhodium compounds, such as [RhCl(CO)2]2, RhCl3-3H2O, and [RhCl(COD)]2, as well as palladium(II) acetate in conjunction with potassium carbonate as catalysts. The study concluded that triarylbismuthines react with CO in the presence of these catalysts to produce diaryl ketones and methyl benzoates, with the reaction pathway involving the oxidative addition of a C-Bi bond to the transition metals, followed by aryl migration and further reaction with CO to form the carbonylated products.
10.1021/acs.orglett.5b00650
This research investigates the reactivity of organolithium reagents with various carbonyl compounds, specifically esters, amides, and ketones, using Rapid Injection NMR (RINMR) techniques. The purpose is to elucidate the reaction mechanisms and intermediates involved, as well as to understand the unusual reactivity patterns observed in these reactions. The study found that alkyllithium reagents react unexpectedly fast with amides compared to esters and ketones. Key chemicals used include 4-fluorophenyllithium (ArLi), n-butyllithium (n-BuLi), methyl benzoate (ester), and benzamide (amide). The researchers identified two reactive intermediates in the reaction of ArLi with esters: a homodimer of the tetrahedral intermediate and a mixed dimer with ArLi. They concluded that the ArLi dimer, rather than the monomer, is the reactive species in these reactions. The study also explored the potential synthetic applications of these findings, though limitations were noted due to the specific conditions required for the reactions to proceed efficiently.
10.1246/cl.1981.1193
The research aimed to develop a new method for the generation of vinyloxyboranes, which are key intermediates for the aldol reaction, a crucial process in organic chemistry for constructing acyclic compounds with multiple chiral centers. The team successfully synthesized phenyl-substituted vinyloxyboranes by acylating boron-stabilized carbanions with methyl benzoate. These vinyloxyboranes were then reacted with aldehydes to yield cross-aldols in good yields, demonstrating excellent diastereoselection in the formation of erythro and threo aldols. The study concluded that the use of methyl benzoate as an acylating reagent provided a novel one-pot procedure for the cross-aldol reaction, consisting of two continuous carbon-carbon bond formations, and resulted in high yields of the desired products without the formation of undesired enol esters. The chemicals used in this process included 1-alkynes, 9-borabicyclo[3,3,1]nonane (9-BBN), methyllithium, and various benzoic acid derivatives.
10.1039/C29690000220
The study investigates the photochemical synthesis of benzocyclopropenone (IVa) through the decomposition of lithium 3-p-tolyl sulphonylamino-1,2,3-benzotriazin-4(3H)-one (Ia) and its 6-chloro-analogue (Ib). The precursor compounds are prepared by diazotization of anthranilic acid toluene-sulfonohydrazides and subsequent treatment with lithium hydride or lithium methoxide. Upon UV excitation, Ia decomposes to yield lithium toluene-p-sulphonate, methyl benzoate, and o-methoxybenzoic acid toluene-p-sulphonohydrazide, while Ib gives lithium toluene-p-sulphonate, methyl p-chlorobenzoate, and 5-chloro-2-methoxy-benzoic acid toluene-p-sulphonohydrazide. The formation of p-chlorobenzoate suggests the involvement of a benzocyclopropenone intermediate (IVb) in the reaction mechanism, which undergoes hemiacetal formation and Favorskii ring-opening to produce the ester. The study also explores the thermolysis of Ia in triglyme, which yields triptycene, possibly via decarbonylation of IVa to form benzyne (VIIIa), and the photolysis of Ib in benzene, producing a small amount of p-chlorobenzophenone.
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