Danheiser annulation aromatic

The Danheiser annulation, in its classic form, is the Lewis acid-catalyzed reaction of an a,yff-unsaturated ketone 1 with a trimethylsilylallene 2 to form a silyl cyclopentene 3. More broadly, the Danheiser annulation ecompasses reactions of silylallenes 4 with electrophilic double bonds to form cyclic products 5, usually under Lewis acid catalysis. The Danheiser annulation should not be confused with other annulation processes developed by Danheiser, such as Danheiser s aromatic annulation and the Stork-Danheiser alkylation. ... 

The Danheiser annulation [86] between cyclobutenone 127 and the silylated ynol 128 led to the formation of a resorcinol intermediate, which was converted to the tetrasu-bstituted aromatic derivative 129 after iododestannylation. 

R.L. Danheiser and co-workers generated a key vinylketene intermediate via tandem Wolff rearrangement-ketene-alkyne cycloaddition to utilize it in a photochemical aromatic annulation reaction Danheiser benzannulation) for the total synthesis of the phenalenone diterpene salvilenone. ... 

Danheiser, R. L., Nishida, A., Savariar, S., Trova, M. P. Trialkylsilyloxyalkynes synthesis and aromatic annulation reactions. Tetrahedron Lett. 1988, 29, 4917-4920. 

Danheiser and coworkers have developed a convenient synthetic approach to useful, highly substituted, aromatic compounds by the reaction of alkoxyacetylenes with cyclobutenone derivatives (equation 61) . The mechanism of this annulation is similar to the analogous reaction of siloxyacetylenes (equation 31, Section II.D.2) and the key step is a [2+2] cycloaddition of alkoxyacetylene with a vinylketene intermediate. ... 

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