Refernces
10.1021/jo00347a060
The research focuses on the novel p' metalations of α,β-unsaturated tertiary amides and their subsequent reactions with various electrophiles, which is a new approach to p' substitution of α,β-unsaturated carboxylic acid derivatives. The purpose of this study was to explore the potential of diisopropyl tertiary amides to undergo p' metalation at low temperatures, leading to stable lithio-α,β-unsaturated amides that can react with a variety of electrophiles, including cases where five-membered rings are formed. The conclusions drawn from the research indicate that this method is effective for achieving substitution at the p' position and has significant synthetic potential, as demonstrated by the successful preparation of the p'-lithiomethacrylate synthon and the control of syntheses with α,β-unsaturated carboxylic acid derivatives. The chemicals used in the process include sec-butyllithium, N,N-diisopropyl-1-cyclohexenecarboxamide, and a range of electrophiles such as deuterium oxide, alkyl halides, ketones, and N,N-dimethylbenzamide, among others.
10.1039/b810988e
The research focuses on the dynamic thermodynamic resolution of N-Boc-2-lithiopiperidine using chiral ligands, with the aim of enhancing the asymmetric synthesis of 2-substituted piperidines. The study explored the use of 26 chiral diamino-alkoxide ligands to achieve selectivities of up to 85:15 for the enantiomers of the organolithium compound. Key chemicals used in the process include N-Boc-piperidine, sec-butyllithium, TMEDA (tetramethylethylenediamine), and a variety of chiral ligands. The researchers found that certain ligands, particularly those derived from isoleucine and with a branched (iPr) substituent alpha to the nitrogen atom, significantly improved selectivity.
10.1021/ja00455a071
The study investigates the use of a-chloro-a-trimethylsilyl carbanion (CTC) as a reagent for homologation of ketones and aldehydes via a,?-epoxysilanes. The researchers deprotonated a-chloromethyltrimethylsilane with sec-butyllithium in THF containing TMEDA to generate CTC. This carbanion was found to be comparatively stable and reacted with various ketones and an aldehyde to form a,?-epoxysilanes. The study demonstrated that these epoxysilanes can be converted into aldehydes and their derivatives with high yields and purity. The procedure is versatile and allows for further elaboration of the products. The study also highlighted the potential of a,?-epoxysilanes as precursors to carbonyl groups and other functional groups.
10.1021/ja00721a042
The research explores a novel method for the introduction of two carbon appendages at a carbonyl carbon, with applications in double chain branching and spiro annulation operations. The study aims to replace carbonyl oxygen with two functionalized carbon substituents that can be further elaborated into rings or more complex chains. The method involves a two-step sequence: first, the formation of allyl enol ethers using ylides, and second, the thermolysis of these enol ethers to yield doubly branched unsaturated aldehydes. Key chemicals used include allyloxymethyltriphenylphosphonium chloride and sec-butyllithium for the formation of ylides, and various carbonyl compounds such as cyclohexanone and benzaldehyde for the branching-annulation sequence. The study also introduces modifications to broaden the scope of the method, such as using diethyl allylthiomethylphosphonate and red mercuric oxide to promote the thio-Claisen rearrangement. The results demonstrate the utility of this method in synthesizing a variety of spiro systems and complex chains, with satisfactory yields and elemental analyses. The research concludes that this two-step sequence is a valuable and flexible approach for the synthesis of complex organic structures.
10.1021/ja056076i
The study presents a novel method for the intermolecular R-arylation and vinylation of amides through palladium-catalyzed coupling of aryl and vinyl bromides with zinc enolates of amides. The researchers developed reactions using three different types of zinc enolates, achieving high yields with a variety of bromoarenes, including those with functional groups such as cyano, nitro, ester, keto, fluoro, hydroxyl, or amino. The use of zinc enolates, as opposed to alkali metal enolates, significantly expands the scope of amide arylation by allowing reactions at room temperature or 70 °C and by tolerating a broader range of functional groups. The study also introduces the use of morpholine amides, which are precursors to ketones and aldehydes, in the arylation process. The reactions were facilitated by catalysts bearing hindered pentaphenylferrocenyl di-tert-butylphosphine (Q-phos) or the highly reactive, dimeric Pd(I) complex {[P(t-Bu)3]PdBr}2, offering a mild and efficient approach to synthesize R-aryl carbonyl compounds, which are prevalent in pharmaceuticals and biologically active compounds.
10.1021/jo00179a002
The research focuses on the synthesis of 3-aryl-3,4-dihydroisocoumarin derivatives, including the natural products hydrangenol and phyllodulcin, using a benzamide directed ortho metalation strategy. The purpose of the study was to develop an efficient and general method for synthesizing these compounds, which are of pharmacological interest due to their potential antifungal and sweetening properties. The researchers utilized various benzamides, such as N,N-diethyl-2-methylbenzamide and N,N-dimethyl-2-methoxybenzamide, along with reagents like lithium diisopropylamide (LDA) and sec-butyl lithium, to achieve the desired metalation and subsequent reactions. The conclusions drawn from the study indicate that the benzamide directed metalation approach is a powerful and adaptable method for synthesizing alkoxy-substituted isocoumarins, which are difficult to prepare by classical routes.
10.1021/om00106a027
The research focuses on the synthesis and reactions of tungsten-iron heterobimetallic complexes. The study involves the preparation of organometallic cyclopentadienyl-substituted phosphines, which are used to synthesize heterobimetallic compounds. Key chemicals used in the research include cyclopentadienyliron dicarbonylmethyl (1), cyclopentadienyltungsten tricarbonylmethyl (2), and chlorodiphenylphosphine. The researchers also utilized various reagents such as sec-butyllithium for lithiation, trimethylamine N-oxide for ligand substitution, and sodium borohydride for reduction reactions. The study explores the interactions and transformations of these complexes, including the formation of heterobimetallic cations and anions, and investigates their potential for unique transformations of organic substrates. The research also includes the determination of the X-ray structures of some of the synthesized compounds to understand their geometric configurations and interactions between the metal centers.
F,
C,
N
