Stereoselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis
作者:Matthew Brichacek、Lindsay A. Batory、Jon T. Njardarson
DOI:10.1002/anie.200906830
日期:2010.2.22
applicable, catalytic, and stereoselective vinyl oxirane ringexpansion is described (see scheme; hfacac=hexafluoroacetylacetonate). The stereoselectivity was influenced by several reaction parameters, and kinetic studies support a mechanistic proposal involving the in situ formation of a more reactive catalytic species. This ring‐expansion reaction has been employed in the asymmetric total synthesis
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.
Tandem Transformations via Friedel–Crafts Acylation Followed by a Ring-Expansion, Ring-Opening, and Cycloisomerization Sequence
作者:Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.8b03881
日期:2019.2.1
A tandem synthetic route to a diverse array of cyclic compounds has been developed from Friedel–Craftsacylation of alkynes followed by the microwave irradiation of β-chlorovinyl ketone intermediates. The stereoisomeric β-chlorovinyl ketone intermediates smoothly underwent a thermal α-vinyl enolization and ring expansion to vinyl and carbocyclic furans as well as cyclopetene derivatives in good to