title: Gold catalysis: domino reaction of en-diynes to highly substituted phenols.
abstract: By Sonogashira coupling of 1,7-heptadiynes and 1,8-octadiynes with 2-iodoallyl alcohols, various substrates that bear a 2-alkynylallyl alcohol moiety tethered to an additional alkyne were prepared in one step. Subjection to nitrogen acyclic carbene (NAC)/gold(I) catalysts delivered highly substituted phenols in an efficient domino reaction. Furan derivatives were formed as intermediates; this was proven by in situ NMR spectroscopy. The uncommon substitution pattern of these furans opens the way for a selective formation of phenols that contain the hydroxyl group in the meta position to the ring junction, which previously was not possible by gold-catalyzed furan-yne cyclization. Furthermore, interesting mechanistic insights were obtained by products derived from secondary allyl alcohols. In this case, in addition to the phenolic compounds, a ketone is formed by 1,2-alkyl shift.
authors.affiliation: Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany. hashmi@hashmi.de
authors.forename: A Stephen K
authors.initials: AS
authors.lastname: Hashmi
authors.forename: Tobias
authors.initials: T
authors.lastname: Häffner
authors.forename: Matthias
authors.initials: M
authors.lastname: Rudolph
authors.forename: Frank
authors.initials: F
authors.lastname: Rominger