Short total syntheses of both the putative and actual structures of the clerodane diterpenoid (+/-)-sacacarin by double annulation.
[reaction: see text] The putative structure of the naturally occurring clerodane diterpenoid (+/-)-sacacarin has been prepared in only 10 steps, six of which are C-C bond-forming steps, in a chemo-, regio-, and diastereoselective manner. The key part of the synthesis is the double annulation (double Michael, Pinner, and Dieckmann reaction) of a tethered carbon diacid and 3-butyn-2-one. A corrected structure for sacacarin is proposed, and the structure is proven by synthesis.
Grossman
R B
RB
Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA. rbgros1@uky.edu
Rasne
R M
RM
D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008519:Medicine, Traditional; D015394:Molecular Structure; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry
D004224:Diterpenes; D005663:Furans; D010936:Plant Extracts; C447981:sacacarin