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).
Rhodium(I)-Catalyzed Decarbonylative Spirocyclization through CC Bond Cleavage of Benzocyclobutenones: An Efficient Approach to Functionalized Spirocycles
作者:Tao Xu、Nikolas A. Savage、Guangbin Dong
DOI:10.1002/anie.201310149
日期:2014.2.10
The rhodium‐catalyzed formation of all‐carbon spirocenters involves a decarbonylative coupling of trisubstituted cyclic olefins and benzocyclobutenones through CC activation. The metal–ligand combination [Rh(CO)2Cl}2]/P(C6F5)3 catalyzed this transformation most efficiently. A range of diverse spirocycles were synthesized in good to excellent yields and many sensitive functional groups were tolerated