Strategy Evolution in a Skeletal Remodeling and C–H Functionalization-Based Synthesis of the Longiborneol Sesquiterpenoids
作者:Robert F. Lusi、Goh Sennari、Richmond Sarpong
DOI:10.1021/jacs.2c08136
日期:2022.9.21
Detailed herein are our synthesisstudies of longiborneol and relatednaturalproducts. Our overarching goals of utilizing a “camphor first” strategy enabled by skeletal remodeling of carvone, and late-stage diversification using C–H functionalizations, led to divergent syntheses of the target naturalproducts. Our initial approach proposed a lithiate addition to unite two fragments followed by a Conia-ene
β-carbons. With substrates bearing nonequivalent γ-C–H bonds, the factors governing site-selectivity have been uncovered. Most remarkably, by manipulating the absolute chirality of the catalyst, γ-lactonization at methyl groups in gem-dimethyl structural units of rigid cyclic and bicyclic carboxylic acids can be achieved with unprecedented levels of diastereoselectivity. Such control has been successfully