[3]DendrAl(l)ene! A new synthesis of [3]dendralenes is based on a Rh(III) -catalyzed alkenyl CH activation and coupling reaction with allenyl carbinol carbonates (see scheme; DG=directing group). A variety of [3]dendralenes with diverse substitution patterns are accessible with good efficiency. The reaction is highly stereoselective and compatible with different directing groups and numerous functional groups.
An efficient and highly asymmetric ruthenium-N-heterocyclic carbene-catalyzed hydrogenation of substituted thiophenes and benzothiophenes is described, providing a new strategy for the formation of valuable enantiomerically pure tetrahydrothiophenes and 2,3-dihydrobenzothiophenes.
H2‐O‐T! Aromatic O‐heterocycles are a challenging substrates for asymmetric hydrogenation (H2). An in situ formed chiral N‐heterocyclic carbene (NHC) ruthenium complex allows the high yielding, completely regioselective, and highly asymmetric hydrogenation of substituted benzofurans at room Temperature, giving valuable 2,3‐dihydrobenzofurans (see scheme).
Two to four! Readily available flavones and chromones were efficiently converted into four valuable chiral classes of O‐heterocycles—flavanones, chromanones, flavanols, and chromanols—by means of an enantioselective Ru/NHC‐catalyzed hydrogenation process (see scheme; NHC=N‐heterocyclic carbene, PCC=pyridinium chlorochromate).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.