An efficient, stereocontrolled synthesis of (6S,7S,8S,8aR)-6,7,8-trihydroxyindolizidine (alias 1-deoxy-7,8-di-epi-castanospermine) (14) has been developed, which exploits an asymmetric vinylogous Mukaiyama aldol reaction (VMAR) between N-(tert-butoxycarbonyl)-2-(tert-butyldimethylsilyloxy)pyrrole (1) and 2,3-O-isopropylidene-D-glyceraldehyde (2) to construct the initial pyrrolidine building blo...

Hyperforin is a constituent of St. John's wort and coexists with the singlet oxygen sensitizer hypericin. Density functional theory, molecular mechanics and Connolly surface calculations show that accessibility in the singlet oxygen "ene" reaction favors the hyperforin "southwest" and "southeast" prenyl (2-methyl-2-butenyl) groups over the northern prenyl groups. While the southern part of hype...

N-Alkylnitrilium and N,N-dialkylcyanamidium salts 1 and 2 undergo ene reactions with cyanamides 4 to afford 2-azoniaallene salts 7 and 9 in which the N-alkylnitrilium salts 1 react as the ene, and the cyanamides 4 react as the enophile components. Competing with the ene reaction, N-alkylnitrilium salts 1 undergo [2++2+2] cycloaddition to furnish triazinium salts 8. 2-Azoniaallene salts react wi...

The title 20-crown-6 unit, C(28)H(30)Br(2)O(6)·CH(2)Cl(2), consisting of three benzo groups and triethyl-ene glycol was prepared from the reaction of 1,2,4,5-tetra-kis-(bromo-meth-yl)benzene and bis-phenol in the presence of sodium hydride. In the crystal, one O atom of the central ethyl-ene glycol in the triethyl-ene glycol unit exhibits an exo conformation as a result of intra-molecular C-H⋯O...

Anaerobic benzoate degradation by the phototrophic bacterium Rhodopseudomonas palustris has been proposed to proceed via aromatic ring reduction reactions leading to cyclohex-1-ene-1-carboxyl-coenzyme A (CoA) formation. The alicyclic product is then proposed to undergo three beta-oxidation-like modifications resulting in ring cleavage. Illuminated suspensions of benzoate-grown cells converted [...

This work described a simple and efficient method for the synthesis of 1-azabicyclo[3.1.0]hexane-3-ene derivatives. arylidenmalononitriles and hydroxylamine hydrochloride in the presence of NaOH, under microwave irradiation and solvent-free conditions produced the titled compounds in good to excellent yields. Using of simple chemicals, short reaction times, and solvent-free conditions, high yie...

The catalytic effect of various Lewis acids (LAs) on the ene reaction between propene (ene) and but-3-en-2-one (enophile) was studied quantum chemically using density functional theory with coupled-cluster theory. LAs efficiently accelerate by lowering barrier up to 12 kcal mol?1 compared uncatalyzed reaction. Our detailed activation strain Kohn-Sham molecular orbital analyses reveal that coord...

N-Substituted amides of endo-3-(3-methylthio-1,2,4-triazol-5-yl)bicyclo[2.2.1]hept-5-ene-2-carboxylic acid and 1-(5-methylthio-1,2,4-triazol-3-yl)cyclohexane-2-carboxylic acid were prepared by the condensation reaction of endo-S-methyl-N1-(bicyclo[2.2.1]hept-5-ene-2,3-dicarbonyl)isothiosemicarbazide and S-methyl-N1-(cyclohexane-2,3-dicarbonyl)isothiosemicarbazide with primary amines. The synthe...

Gold-catalyzed intermolecular reaction leading to dihydronaphthalene derivatives in one pot from two equivalents of ynones with respect styrene is uncovered. The [4+2] Diels–Alder cycloaddition and styrenes catalyzed by a mono-gold(I) complex the conjugated acid provide an unstable 3,8a-dihydronaphthalene subsequently undergo ene-type ?-activated ynone afford multi-component coupling products. ...