1,2-Annulated pyrrolo[2,1,5-de]quinolizin-5-ones (cycl[3.3.2]azin-5-ones) 6a-6k, 8a-8b and 9 have been synthesized by one pot tandem reactions of 2-acetyl-N-phenacylpyridinium bromides (1a-1d) with electron-deficient cyclic alkenes (N-alkyl(aryl)maleimides, benzoquinones and naphthoquinone) in the presence of sodium carbonate as a base and tetrakispyridinecobalt(II) dichromate (TPCD) as an oxid...

Mass spectral fragmentation pathways of four doubly unsaturated aldehyde N,N-dimethylhydrazones were investigated using EI-MS and tandem mass spectrometry (MS/MS) under electron ionization and collisionally activated decomposition (CAD) conditions. Cyclopentene extrusion was found to be slightly favored over cyclohexene loss in a hydrazone capable of losing either cycloalkene. Evidence for the ...

The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO(-) or MeO(-)) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transfor...

A multitasking C-silylation strategy using the readily available compound 26 as a surrogate for cinnamic acid represents the key design element of a total synthesis of all known members of the ipomoeassin family of resin glyosides. This protecting group maneuver allows the unsaturated acids decorating the glucose subunit of the targets to be attached at an early phase of the synthesis, prevents...

A one step, regioselective allylic fluorination of alkenes is reported in which electrophilic and nucleophilic sources of fluorine act synergistically to afford rearranged allylic fluorides over alternative vicinal dihalides. The reaction occurs under exceptionally mild conditions and without need for prefunctionalization or transition metal catalysts. The fluorination of cyclic alkenes and mon...

The deprotonation of 1,3-dimesitylbenzimidazolium tetrafluoroborate with a strong base afforded 1,3-dimesitylbenzimidazol-2-ylidene (BMes), which was further reacted in situ with rhodium or ruthenium complexes to afford three new organometallic products. The compounds [RhCl(COD)(BMes)] (COD is 1,5-cyclooctadiene) and cis-[RhCl(CO)2(BMes)] were used to probe the steric and electronic parameters ...

It was previously reported that the palladium-catalyzed cross-coupling reaction of 1-alkenylboron compounds with various vinylic or aryl halides in the presence of base provides the corresponding coupling products in high yields, stereoand regioselectively. The recent progress of such reactions, including the reaction of sterically hindered arylboronic acids with sterically hindered haloarenes,...