Synthesis and evaluation of colletoic acid core derivatives

Cortisol homeostasis has been linked to the pathogenesis of metabolic syndrome (MetS), since it stimulates hepatic gluconeogenesis and adipogenesis. MetS is classified as a constellation of health conditions that increase the risk of type 2 diabetes and cardiovascular disease. Intracellular cortisol levels are regulated by 11β-hydroxysteroid dehydrogenase (type 1 and type 2) in a tissue dependent manner. The type 1 enzyme (11β-HSD1) is widely expressed in glucocorticoid targeted tissues and is responsible for the conversion of cortisone to the active cortisol. Local reduction of cortisol regeneration presents a potential strategy for MetS treatment. Recently we disclosed the total synthesis of (+)-colletoic acid as a potent 11β-HSD1 inhibitor. Herein, we describe our improved processing chemistry for the synthesis of the colletoic acid core to access a diverse number of derivatives for evaluation against 11β-HSD1. The Evan's chiral auxiliary was utilized to construct the acyclic precursor 12 to afford the acorane core 9 using a modified Heck reaction in excellent chemical yields. The colletoic acid core derivatives showed modest activity against 11β-HSD1 and will serve for further biological evaluation.