title: A formal total synthesis of (+/-)-halichlorine and (+/-)-pinnaic acid.
abstract: [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.
authors.affiliation: School of Pharmacy, Tokyo University of Pharmacy & Life Science, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Sakae
authors.initials: S
authors.lastname: Aoyagi
authors.forename: Chihiro
authors.initials: C
authors.lastname: Kibayashi