A unique alternative to the -spirocyclization for activation of compounds containing the duocarmycin SA alkylation subunit was established involving indole NH deprotonation and subsequent cyclopropane formation. The structural characterization of an alternative spirocyclization product, and the establishment of its relative reactivity, intrinsic reaction regioselectivity, biological activity, and DNA alkylation properties (selectivity, rate, and efficiency) including the isolation, characterization, and quantitation of its adenine N3 adduct, are disclosed.
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| http://dx.doi.org/10.1021/ja806593w | DOI Listing |
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As a class of readily available and multifunctional building blocks, the chemistry of 4-alken-2-ynyl carbonates remains to be explored. Presented herein is a palladium-catalysed cascade transformative reaction between 4-alken-2-ynyl carbonates and -functionalised activated alkenes. Achiral 1,1-bisalkyl-4-alken-2-ynyl carbonates undergo highly regioselective propargylic substitution with -hydroxyphenyl-tethered activated alkenes, and an auto-tandem vinylogous addition, unusual central-carbon Tsuji-Trost alkylation, protonation and β-H elimination process is followed to furnish fused and spirocyclic frameworks with high structural complexity.
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