Decorated Cyclopentadienes from Acetylene and Ketones in Just Two Steps

The products of the one-pot assembly of acetylene and ketones in the KOH/DMSO system, 7-methylene-6,8-dioxa­bicyclo­[3.2.1]­octanes, undergo an acid-catalyzed (CF₃COOH, room temperature) rearrangement to rarely substituted cyclopenta­dienes in good-to-excellent yields. The mechanism of the rearrangement has been supported by the isolation and corresponding transformations of two intermediates

Regioselective N(2)-H-functionalization of thiosemicarbazones of aromatic and heteroaromatic aldehydes with acrylonitrile

<p>Regioselective N(2)-H-cyanoethylation of thiosemicarbazones of aromatic and heteroaromatic aldehydes with acrylonitrile proceeds under mild conditions (14% KOH, acetone/H₂O, 35 °C, 6–21 h) to afford 1-(2-сyanoethyl)-2-[(<i>E</i>)-aryl(heteroaryl)methylidene]-1-hydrazinecarbothioamides in up to 74% yields. The synthesized thioamides are promising precursors of novel families of functionalized thiosemicarbazones as exemplified by hydrolysis of their cyano group to the corresponding amido function (46.5–60% yields).</p

Domino Assembly of Trifluoromethylated N,O-Heterocycles by the Reaction of Fluorinated α‑Bromoenones with Amino Alcohols

A highly efficient method for the selective synthesis of trifluoromethylated morpholines (4-oxa-1-azabicyclo[4.1.0]­heptanes) and so far unknown 1,4-oxazepanes (2,8-dioxa-5-azabicyclo[5.1.0]­octanes) based on a domino reaction of fluorinated α-bromoenones with β-amino alcohols was elaborated. The assembly of both heterocyclic systems is initiated by an aza-Michael reaction followed by intramolecular cyclization. The conditions for total control of selectivity of the reaction were found

Synthesis of Acyl Terphenyls and Higher Polyaromatics via Base-Promoted C–H Functionalization of Acetylarenes with Arylacetylenes

KO<i>^t</i>Bu/DMSO-promoted C–H functionalization of acetylarenes with arylacetylenes (100 °C, 30 min), generating β,γ-ethylenic ketones, triggers upon further heating (100 °C, 4 h, with or without acidifying additive) the cascade assembly of acyl terphenyls and higher polyaromatics in good yields