Abstract
Alkyl-, alkoxy-, and aryloxy-substituted conjugated enynes 1 in the presence of Pd(PPh3)4 catalyst smoothly underwent the regiospecific [4 + 2] cycloaddition reaction with conjugated alkyl- and alkoxy-substituted symmetric diynes 2 to give multisubstituted aryl ethers 3 in good to high yields. Benzannulation of enynes 1d-g with unsymmetric diyne 6, possessing alkyl and alkoxy groups at acetylenic terminii, in most cases produced an aromatic product 8 with an alkoxy group of diyne attached to the ethynyl moiety of the aromatic product. Remarkably, alkoxy-substituted diynes 2c and 6 underwent the benzannulation reaction with 1 at an unusually low temperature of 0 °C! One-pot consecutive benzannulation of alkyl-substituted enynes 1d,e and alkoxy-substituted enynes 1f,g with alkoxy-substituted diynes 2c and 6 followed by protonolysis with TsOH afforded coumaranones 9a-c and 10 in reasonable to high overall yields.
Original language | English (US) |
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Pages (from-to) | 568-572 |
Number of pages | 5 |
Journal | Journal of Organic Chemistry |
Volume | 65 |
Issue number | 2 |
DOIs | |
State | Published - Jan 28 2000 |
Externally published | Yes |
ASJC Scopus subject areas
- Organic Chemistry