Bioinspired Total Synthesis of Agelastatin A

A one‐two punch : Two potentially biosynthetically relevant cyclizations of a keramadine analogue give agelastatin A (see scheme). A diastereoselective C‐ring formation, which proceeds through a 5‐ exo ‐trig cyclization or a Nazarov cyclization of a red‐colored N ‐acyliminium intermediate, generates the three contiguous stereocenters of the cyclopentane core. A silica gel assisted cyclization of a nagelamide J analogue gives agelastatin A.