Enantioselective Synthesis of Myrtucommulone A

Myrtucommulone A (1), which was isolated from myrtle and other species of the myrtaceae family, was synthesized through an enantioselective Michael addition of isobutyryl phloroglucinol (5) to isobutylidene syncarpic acid (4) that was induced by a chiral Al–Li–BINOL (1,1′‐bi‐2‐naphthol) complex [(S,S)‐ALB]. Because there is significant steric crowding in Michael acceptor 4, myrtucommulone A (1) was obtained with an ee value of 70 % along with meso‐1 in 77 % chemical yield. Myrtucommulone A (1) is a phloroglucinol derivative that is isolated from myrtle (Myrtus communis) and shows antibiotic, anti‐inflammatory, and apoptosis‐inducing activities. For pharmacological and racemization studies, we synthesized (+)‐1 enantioselectively with an ee value of 70 % in two steps from isobutyryl phloroglucinol, isobutylidene syncarpic acid (4), using first (S,S)‐8 and then (R,R)‐8.