Synthesis of dibenzocyclohepten-5-ones by electrophilic iodocyclization of 1-([1,1'-biphenyl]-2-yl)alkynones
Yu Chen1, Chenlong Huang, Xiaochen Liu
1Department of Chemistry and Biochemistry, Queens College and the Graduate Center of the City University of New York , 65-30 Kissena Boulevard, Flushing, New York 11367, United States.
Abstract:
A synthesis of iodo-substituted dibenzocyclohepten-5-ones by the iodine monochloride (or iodine)-induced intramolecular 7-endo-dig cyclization of 1-([1,1'-biphenyl]-2-yl)alkynones is reported. Detailed investigations on the substituent effects during the electrophilic iodocyclization of the alkynones show that they play a crucial role in determining the reaction pathways of the cyclization. By modifying the substitution pattern on the alkynone substrates, the cyclization takes place regioselectively, leading to either dibenzocyclohepten-5-ones, via a 7-endo-dig cyclization, or spiroconjugated compounds, via a 6-endo-dig cyclization.
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