Straightforward Access to the Dispirocyclic Framework via Regioselective Intramolecular Michael Addition
Weilun Cao1, Junmin Dong1, Xuan Pan1
1State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China.
None:
In this article, an efficient and straightforward protocol for the construction of complex dispirocyclic skeletons via regioselective intramolecular Michael addition is presented. Diverse dispirocyclic compounds were synthesized under mild and transition-metal-free conditions with good to excellent yields. Most stereoisomers were conveniently separated by column chromatography, and their relative configurations were identified by single-crystal X-Ray diffraction of representative compounds. A scale-up experiment validated the practicality of this method. In an in vitro assay, some dispirocyclic compounds exhibited potent cytotoxicity with an IC50 value of 10-6 mol/L.
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