Investigation of the behavior of arenediazonium salts with olefins in BmimPF6

The palladium-catalyzed reactions of olefins with arenediazonium salts in ionic liquids were investigated. For methyl acrylate and methyl acrylonitrile, normal Heck cross-coupling products are obtained in good yields. However, highly selective dimerization products are formed in excellent yields for styrenes. The catalyst system can be recycled.     

Convenient and efficient stereoselective synthesis of (2Z)-2-(chloromethyl)alk-2-enoates using iron(III) or indium(III) chloride

The stereoselective synthesis of (2Z)-2-(chloromethyl)alk-2-enoates has been achieved efficiently and in high yields and in short reaction times from Baylis-Hillman adducts, 3-hydroxy-2-methylene-alkanoates, by treatment with FeCl₃ or InCl₃ at room temperature.     

Conversion of some Natural Dienamides to the Corresponding β, γ - Unsaturated Amides using Mg/MeOH

The naturally occurring dienamides, piperine, piperlonguminine, guineensine, brachystamide-B and pergumidiene were converted to the corresponding β, γ-unsaturated amides by using Mg/MeOH.     

Pd-catalyzed cross-coupling of Baylis-Hillman acetate adducts with bis(pinacolato)diboron: an efficient route to functionalized allyl borates

The cross-coupling of Baylis-Hillman acetate adducts and bis(pinacolato)diboron proceeds readily in high yields in the presence of palladium catalyst to produce 3-substituted-2-alkoxycarbonyl allylboronates. These allylboronates can be transformed to stable allyl trifluoroborate salts by addition of excess aqueous KHF2. Both the allylboronate and allyltrifluoroborate derivatives react with aldehydes to afford functionalized homoallylic alcohols stereoselectively.     

Palladium-catalyzed cross-coupling of acetates of Baylis-Hillman adducts and potassium organotrifluoroborates

[reaction: see text] The cross-coupling of potassium organotrifluoroborates and acetates of Baylis-Hillman adducts proceeds readily in moderate to excellent yield in the presence of Pd(OAc)(2). The reaction tolerates hindered trifluoroborate salts, and the process is stereoselective.     

Chemo-enzymatic synthesis of both enantiomers of rugulactone

The synthesis of both the (R)- and (S)-enantiomers of the natural product rugulactone has been achieved. Candida rugosa lipase hydrolyzes the butyrate ester of the protected 3-hydroxy homoallylic alcohol with very high enantioselectivity (E = 244) and provides the key intermediates with high enantiomeric purity (ee 98–99%) and excellent yields.     

Asymmetric synthesis of Goniothalesdiol A from (R)-2,3-O-cyclohexylidine glyceraldehyde

Goniothalesdiol A 1 has been synthesized from (R)-2,3-O-cyclohexylidine glyceraldehyde with high stereoselectivity and 22% overall yield in 11 simple steps. The key features of the synthetic strategy include the stereocontrolled allylation of (R)-2,3-O-cyclohexylidine glyceraldehydes; the cross-metathesis with a Grubbs’s second generation catalyst, and the intramolecular base-catalyzed oxy-Michael addition for the formation of the tetrahydropyran ring.     

A novel stereoselective synthesis of (−)-β-conhydrine from (R)-2,3-O-cyclohexylidine glyceraldehyde

A novel stereoselective synthesis of (−)-β-conhydrine is achieved. Stereoselective Grignard reaction of (R)-2,3-O-cyclohexylidine glyceraldehyde with ethyl magnesium bromide, chelation controlled stereoselective Grignard reaction of allyl imine derivative with allyl magnesium bromide, and ring-closing metathesis (RCM) of the diallyl product provides (−)-β-conhydrine in high yield.     

The use of potassium alkynyltrifluoroborates in Mannich reactions

Potassium alkynyltrifluoroborates react with amines and salicylaldehydes in the presence of benzoic acid to generate highly functionalized amines. Ionic liquids such as butylmethylimidazolium tetrafluoroborate (BmimBF₄) are suitable solvents for the reaction.     

Jatrophenone,a novel macrocyclic bioactive diterpene from Jatropha gossypifolia

A novel macrocyclic diterpene, jatrophenone, has been isolated from the whole plant of Jatropha gossypifolia. The structure of the compound was established by detailed studies of its one- and two-dimensional (1D and 2D) NMR spectra. The compound possesses significant antibacterial activity.