AuBr3-Catalyzed [4 + 2] Benzannulation between an Enynal Unit and Enol
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- 27 May 2004
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 126 (24) , 7458-7459
- https://doi.org/10.1021/ja0477367
Abstract
The reaction of enynals 1, including o-alkynylbenzaldehydes, and carbonyl compounds 2 in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 °C gave the functionalized aromatic compounds 3 in high yields. The AuBr3-catalyzed formal [4 + 2] benzannulation proceeds most probably through the coordination of the triple bond of 1 to AuBr3, the formation of a pyrylium auric ate complex via the nucleophilic addition of the carbonyl oxygen atom, the reverse electron demand-type Diels−Alder addition of the enols, derived from 2, to the auric ate complex, and subsequent dehydration and bond rearrangement. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds afforded the corresponding aromatic compounds in good yields.Keywords
This publication has 2 references indexed in Scilit:
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- Functionalized 1,2‐Dihydronaphthalenes from the Cu(OTf)2‐Catalyzed [4+2] Cycloaddition of o‐Alkynyl(oxo)benzenes with AlkenesAngewandte Chemie International Edition in English, 2003