Rh-catalysed [5 + 1] cycloaddition of allenylcyclopropanes and CO: reaction development and application to the formal synthesis of (−)-galanthamine
作者:Cheng-Hang Liu、Zhi-Xiang Yu
DOI:10.1039/c6ob00660d
日期:——
A Rh-catalysed [5 + 1] cycloaddition of allenylcyclopropanes and CO has been developed to synthesize functionalized 2-methylidene-3,4-cyclohexenones. The scope of this methodology has been investigated, showing that various functional groups can be tolerated. Both di- and tri-substituted allenylcyclopropanes can be applied to this cycloaddition and the [5 + 1] cycloadducts with the E configuration
to manzacidins A and D, here we report a highly efficient catalyticasymmetric α-allenylic alkylation reaction of NH2-unprotected aminoacid esters that is promoted by combined chiral aldehyde/palladium catalysis. Fifty examples of unnatural α,α-disubstituted aminoacid esters are reported with good-to-excellent yields and stereoselectivities. Based on this methodology, a key intermediate leading to
Gold-Catalyzed <i>N</i>,<i>O</i>-Functionalizations of 6-Allenyl-1-ynes with <i>N</i>-Hydroxyanilines To Construct Benzo[<i>b</i>]-azepin-4-one Cores
作者:Antony Sekar Kulandai Raj、Balaji S. Kale、Bhanudas Dattatray Mokar、Rai-Shung Liu
DOI:10.1021/acs.orglett.7b02629
日期:2017.10.6
Gold-catalyzedreactions of 6-allen-1-ynes with N-hydroxyanilines afford thermally stable benzoazepin-4-ones in anti-selectivity; these anti-configured products are easily isomerized to their syn-isomers on a silica column. The mechanism of reactions likely involve initial nitrone/allene cycloadditions, followed by skeletal rearrangement of resulting intermediates.