An Efficient Synthesis of 2-CF3-3-Benzylindoles

The reaction of α-CF₃-β-(2-nitroaryl) enamines with benzaldehydes afforded effectively α,β-diaryl-CF₃-enones having nitro group. Subsequent reduction of nitro group by NH₄HCO₂-Pd/C system initiated intramolecular cyclization to give 2-CF₃-3-benzylindoles. Target products can be prepared in up to quantitative yields. Broad synthetic scope of the reaction was shown. Probable mechanism of indole formation is proposed.     

Lewis acid promoted highly stereoselective rearrangement of 2,3-aziridino alcohols: a new efficient approach to beta-amino carbonyl compounds

A new Lewis acid promoted rearrangement reaction of 2,3-aziridino alcohols was discovered, which involved the highly stereoselective construction of a diastereogenic quaternary carbon center and efficient formation of beta-amino carbonyl compounds in excellent yields. A wide variety of Lewis acids were proved to be effective for the reaction, and a possible reaction mechanism was also discussed.     

Chiral base promoted enantioselective rearrangement of organophosphorus epoxides

Cinchona alkaloids serve as effective chiral bases for enantioselective rearrangement of 3,4-epoxyphospholane oxides resulting in the formation of P,C-chirogenic 4-hydroxy-2-phospholene derivatives with up to 52% ee. A stereochemical course of the epoxide rearrangement involving anti β-proton abstraction is proposed. 3,4-Epoxy-1-phospholane-borane rearranges to 4-hydroxy-2-phospholene-borane of 55% ee on treatment with sec-BuLi/sparteine base system.     

Triisobutylaluminium (TIBAL) promoted rearrangement of C-glycosides

Triisobutylaluminium-promoted rearrangement of unsaturated glycosides containing electron-donating aglycons, such as C-aryl glycosides, provides direct access to highly functionalised cyclohexane derivatives.     

Enzymatic resolution of 2,3-epoxyalcohols,intermediates in the synthesis of the gypsy moth sex pheromone

An efficient resolution of 2,3-epoxyalcohols 2a-b were obtained both by enzymatic hydrolysis and transesterification in organic solvent: (25,3R) 2b and (2R,35) 2a thus obtained are chiral synthons for the synthesis of (+)- Disparlure 1.     

Synthesis and Reactions of 3-Halogenated 2-CF3-Indoles

Halogenation of 2-trifluoromethylindole afforded 3-chloro-, 3-bromo- and 3-iodo derivatives in up to 98% yield. Methyl-, benzyl- and tosyl-groups can be installed at the nitrogen atom of prepared indoles in high yields by base catalyzed reaction with the corresponding alkylating (sulfonylating) reagents. A high synthetic utility of the prepared haloindoles in the reaction with various nucleophilies was shown. The reaction with 4-methylthiophenol and copper cyanide afforded the corresponding sulfides and nitriles in high yield. Palladium catalyzed cross-coupling with phenyl boronic acid and phenylacetylene gave the corresponding 3-phenyl-2-CF₃-indoles and acetylenic derivatives in 72–98% yield.     

Silver(I) promoted rearrangement of bishomocubane derivatives

Silver(I) ion catalyzes the conversion of bishomocubane derivatives into dicyclopentadiene derivatives in quantitative yield.     

Dearomatization-bis-alkylation of aromatic and heteroaromatic diesters promoted by Me3SnLi via a stanna-Brook rearrangement

[STRUCTURE: SEE TEXT] Reaction of Me3SnLi with aromatic and heteroaromatic diesters proceeds through a fast stanna-Brook rearrangement that generates an stable bis-enolate which can be regioselectively alkylated and cyclized, in one step, to bicyclic compounds containing 6,5-, 6,6-, and 6,7-fused ring systems.     

1-芳基-3-(5-氯-1,3-二苯基-1H-4-吡唑基)-2,3-环氧-1-丙酮的新重排反应

报导了1-芳基-3-(5-氯代-1,3-二苯基-1H-4-吡唑基)-2,3-环氧-1-丙酮的重排反应, 生成β-(4,5-二氢-1,3-二苯基-5-酮-1H-4-吡唑基)-α-羟基-α-P-甲苯基丙酸, 讨论了反应机理, 并用红外光谱, 核磁共振氢谱, 碳十三核磁共振和微量分析证实了结构.     

Cyclization and rearrangement of 4-(2-methyloxiranyl)-β-lactams promoted by titanocene dichloride/Zn

Enantiopure epoxyalkene-2-azetidinones derived from d-glucosamine by Staudinger reaction gave on treatment for 2 h with titanoncene (III) monochloride generated in situ, bicyclic and tricyclic β-lactams with high regio and stereo-selectivity but with low conversion. For extended reaction times (15-22 h) a rearranged five-membered ring imide was the main reaction product together with the tribactam.     

Aza-Ferrier rearrangement of glycals with amides promoted by molecular iodine

Amidoglycosidation of tri-O-acetyl-d-glucal with different N-nucleophiles such as t-butyl carbamate, N-benzyl carbamate, N-ethyl carbamate, tosyl amide, and mesyl amide has been achieved using an equimolar amount of molecular iodine under mild and neutral conditions to afford the corresponding N-glycosyl amides in good yields with a preferential α-anomeric selectivity. The use of iodine makes this method simple, convenient, and cost-effective. This is the first report on aza-Ferrier rearrangement using molecular iodine.     

Ionic liquid promoted synthesis of 3-(2′-benzothiazolo)-2,3-dihydroquinazolin-4(1H)-ones

3-(2′-Benzothiazolo)-2,3-dihydroquinazolin-4(1H)-ones have been synthesized in high yields in the presence of 1-butyl-3-methylimidazolium bromide [bmim]Br as an ionic liquid; the reaction work-up is simple and the ionic liquid can be easily separated from the product and reused.     

Versatile Fluorine-Containing Building Blocks: β-CF3-1,3-enynes

The development of diversity-oriented synthesis based on fluorine-containing building blocks has been one of the hot research fields in fluorine chemistry. β-CF₃-1,3-enynes, as one type of fluorine-containing building blocks, have attracted more attention in the last few years due to their distinct reactivity. Numerous value-added trifluoromethylated or non-fluorinated compounds which have biologically relevant structural motifs, such as O-, N-, and S-heterocycles, carboncycles, fused polycycles, and multifunctionalized allenes were synthesized from these fluorine-containing building blocks. This review summarizes the most significant developments in the area of synthesis of organofluorine compounds based on β-CF₃-1,3-enynes, providing a detailed overview of the current state of the art.     

Synthesis of 2,3-diaminodihydropyrroles via thioimidate cyclopropane rearrangement

The synthesis of novel 2,3-diaminodihydropyrroles is reported. The key step is a thiomethylimidate cyclopropane rearrangement to afford a pyrrolothiomethylimidate intermediate. Reaction of this intermediate with amines produced the title compounds in good yields. The scope and mechanism of the reaction is discussed.     

Preparation of esters containing an β-CF3 group

Malonates may be converted to esters containing an δ-CF3 group in a two-step process involving bromodifluoromethylation of the malonates followed by decarboxyalkylation-fluorination with fluoride ion in DMSO.     

o.Formylarylazomethylenetriphenylphosphoranes: A facile thermally promoted rearrangement to 3-oxo-indazoline and 4-oxo-dihydroquinazoline derivatives

The $\text{o}$.formylarylazomethylenetriphenylphosphoranes carrying an electron withdrawing group on the ylidic carbon undergo thermal $\text{intra}$ molecular cyclization to 3-oxo-indazolin-2-yl-methylenetriphenylphosphorane derivatives. The latter compounds, and their 1-alkyl derivatives, in turn, undergo thermal and/or acid catalyzed rearrangement to 4-oxo-l,4-dihydroquinazoline derivatives and PPh₃. Some possible reaction mechanisms are discussed, and some synthetic applications of the above reactions are shown.     

Oxy-function promoted hydroboration of conjugated dienes with controlled allylic borane rearrangement

Hydroboration of conjugated dienes is promoted by the hydroxy and methoxy groups, which also control the rearrangement of the initially produced allylic boranes.     

Silica gel promoted environment-friendly synthesis of 2,3-disubstituted 4-thiazolidinones

Three-component one pot silica gel promoted synthesis of 2,3-disubstituted 4-thiazolidinones is described. The method provides rapid and easy access to thiazolidinone compounds in good to excellent yields.