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Isomerization reactions of enesulfonamides and enecarbamates using platinum(II) and silver(I) catalysts

University of British Columbia

The scope of a platinum(II) chloride catalyzed isomerization of enesulfonamides and enecarbamates that proceeds by alkyne activation followed by Friedel-Crafts reaction was investigated. Seven enesulfonamide and enecarbamate derivatives with a variety of aromatics and heteroaromatics were synthesized. Exposure to catalytic platinum chloride generated tetracyclic products in 17 to 78% yield. The regioselectivity of the attack on the alkyne in this reaction varied from 8:1 to 1:0 mixtures of products. Additionally, a silver-catalyzed ring expansion reaction of enesulfonamides containing 2-alkynyl indoles to generate eight-membered rings was investigated. A series of control reactions were performed to determine the mechanism, which was found to proceed by interaction of the catalyst with the indole ring. Thirteen enesulfonamide derivatives containing aromatic, heteroaromatic and carbonyl substituents were submitted to silver and acid catalysis, yielding azocine derivatives in 0 to 97% yield.

Text

2011-03-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/23169

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/