First Total Synthesis of the 4<i>a</i>-Methyltetrahydrofluorene Diterpenoids (±)-Dichroanal B and (±)-Dichroanone

Abstract

[reaction: see text] A simple synthesis of the 4a-methyltetrahydrofluorene diterpenoids (+/-)-dichroanal B and (+/-)-dichroanone has been achieved through a common hexahydrofluorenone intermediate obtained via Pd(0)-catalyzed reductive cyclization of a substituted 2-(2-bromobenzyl) methylene cyclohexane.