Asymmetric Total Synthesis of Natural Lindenane Sesquiterpenoid Oligomers via a Triene as a Potential Biosynthetic Intermediate.

A previously proposed triene of the lindenane skeleton was synthesized, characterized, and identified as the common intermediate for the non-enzymatic synthesis of natural lindenane oligomers through linear, [4+2]-type and [6+6]-type homo- and hetero- dimerization under simulated physiological conditions. As a result, the following six natural products were successfully synthesized through thermal head-to-head, head-to-tail, and head-to-back binding modes: shizukaols A and J, cycloshizukaol A, chlorahupetone F, chlotrichene B, and trishizukaol A.