- A ring expansion-annulation strategy for the synthesis of substituted azulenes. Preparation and suzuki coupling reactions of 1-azulenyl triflates
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(matrix presented) A new strategy for the synthesis of substituted azulenes is reported, based on the reaction of β′-bromo-α-diazo ketones with rhodium carboxylates The key transformation involves intramolecular addition of a rhodium carbenoid to an arene π-bond, electrocyclic ring opening, β-elimination, tautomerization, and trapping to produce 1-hydroxyazulene derivatives. The synthetic utility of the method is enhanced by the ability of the triflate derivatives to participate in Suzuki coupling reactions, as illustrated in a synthesis of the antiulcer drug egualen sodium (KT1-32).
- John L Jr., Kane,Shea, Kevin M.,Crombie, Aimee L.,Danheiser, Rick L.
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p. 1081 - 1084
(2007/10/03)
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