Protecting Groups as Dispersive Directing Groups: Toward the Asymmetric Synthesis of Altemicidin
Wang Y, Platt AP, Gaston R Jr, Paton RS, Trauner DH. Protecting Groups as Dispersive Directing Groups: Toward the Asymmetric Synthesis of Altemicidin. Org Lett. 2026 Jun 26;28(25):7959-7964. doi: 10.1021/acs.orglett.6c01569. Epub 2026 Jun 10. PMID: 42268633.
Abstract
We report progress toward the asymmetric total synthesis of altemicidin, a monoterpene alkaloid featuring a 6-azatetrahydroindane core. A diastereoselective 1,3-dipolar cycloaddition with TMS-diazomethane enabled the construction of a key pyrazoline intermediate. Computational analysis (EDA/NCI) revealed attractive London dispersion forces as the origin of the unexpected stereoselectivity. An effective method to convert the initial silylated 1-pyrazoline into a stable 2-pyrazoline was developed. Selective reductive trifluoroacetylation and SmI2-mediated N-N bond cleavage afforded a 1,3-diamine suitable for further functionalization.