Regioselective Synthesis of Bioactive Polyheterocycles: Sequential [3, 3] Sigmatropic Rearrangements of 6-(4-Aryloxybut-2-yn-1-yloxy)[1]Benzopyran-2-Ones
摘要:
7a-Methyl-13,13a-dihydro-7aH-furo[3,2-c : 5,4-f']bis-[1]benzopyran-3-ones (4a-d) are regioselectively synthesised in 65-75% yields by the sequential rearrangements of 6-(4-aryloxybut-2-yn-1-yloxy)[1]benzopyran-2-ones (3a-d) in refluxing N,N-diethylaniline (15 h). However, addition of toluene-4-sulphonic acid in the reaction mixture improved the yield (80-85%) and reduced the reaction time (10 h).
We disclose here the first palladium-catalyzed Suzuki–Miyaura couplings of aryl ethers functionalized allenylphosphine oxides with arylboronicacids. This new methodology with α-allenyl ethers as starting materials provides a novel approach to generate phosphinoyl 1,3-butadienes and derivatives with medium to excellent yields. The reaction tolerates a variety of functional groups to afford ranges of