A formal total synthesis of (+/-)-halichlorine and (+/-)-pinnaic acid.
[reaction: see text] A stereocontrolled approach for the preparation of the Danishefsky intermediates has been developed starting with the azaspirobicyclic ketone as a common precursor, representing a formal total synthesis of (+/-)-halichlorine and (+/-)-pinnaic acid. This approach involves the construction of the 1,7-disubstituted 6-azaspiro[4.5]decane with the proper stereochemistry established by olefin hydrogenation followed by C-methylation of the spirotricyclic lactam and the subsequent processes involving lactam ring-opening using methyl triflate and RCM to form the azaspirotricyclic quinolizidine skeleton.
Matsumura
Yosuke
Y
School of Pharmacy, Tokyo University of Pharmacy & Life Science, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
Aoyagi
Sakae
S
Kibayashi
Chihiro
C