Gold Catalysis: Efficient 1,3-Induction with Diastereotopic Homopropargyl Alcohols in the Phenol Synthesis
作者:A. Stephen K. Hashmi、Melissa Hamzić、Matthias Rudolph、Martin Ackermann、Frank Rominger
DOI:10.1002/adsc.200900402
日期:2009.10
Furans with diastereotopic alkynyl groups were prepared and then converted to anellated phenols in gold-catalyzed reactions. In all cases a highly diastereoselective reaction was observed. The stereochemical outcome of the 1,3-induction could be assigned by two independent crystal structure analyses, showing a cis-arrangement of the two alkyl substituents on the benzoanellated cyclohexene ring.
reactivity of “furan-ynes” in combination with pyridine and quinoline N-oxides in the presence of a Au(I) catalyst, has been studied, enabling the synthesis of three different heterocyclic scaffolds. Selective access to two out of the three possible products, a dihydropyridinone and a furan enone, has been achieved through the fine-tuning of the reaction conditions. The reactions proceed smoothly at room
leaving group, azide is capable of initiating the generation of a furfuryl cation under the Lewis acid-catalyzed conditions, followed by reacting with the other azide to realize an intermolecular [3 + 2] cycloaddition/furan ring-opening cascade. By extending the reaction time, a fragmentationreaction of resulting furfuryl triazoles occurs to afford 1H-triazoles in high yield. Control studies demonstrated