440677-00-9Relevant academic research and scientific papers
Asymmetric construction of the azaspiro[5.5]undec-8-ene system towards gymnodimine synthesis
Tsujimoto, Takashi,Ishihara, Jun,Horie, Mariko,Murai, Akio
, p. 399 - 402 (2002)
In the course of the synthetic studies on gymnodimine, a potent shellfish toxin, the asymmetric construction of the azaspirocyclic part was achieved by the (-)-siam·Cu(SbF6)2 complex catalyzed intermolecular Diels-Alder reaction in high exo- and enantioselectivities.
Total synthesis of the spirocyclic imine marine toxin (-)-gymnodimine and an unnatural C4-epimer
Kong, Ke,Moussa, Ziad,Lee, Changsuk,Romo, Daniel
supporting information; experimental part, p. 19844 - 19856 (2012/01/12)
The first total synthesis of the marine toxin (-)-gymnodimine (1) has been accomplished in a convergent manner. A highly diastereo- and enantioselective exo-Diels-Alder reaction catalyzed by a bis-oxazoline Cu(II) catalyst enabled rapid assembly of the spirocyclic core of gymnodimine. The preparation of the tetrahydrofuran fragment utilized a chiral auxiliary based anti-aldol reaction. Two major fragments, spirolactam 56 and tetrahydrofuran 55, were then coupled through an efficient Nozaki-Hiyama-Kishi reaction. An unconventional, ambient temperature t-BuLi-initiated intramolecular Barbier reaction of alkyl iodide 64 was employed to form the macrocycle. A late stage vinylogous Mukaiyama aldol addition of a silyloxyfuran to a complex cyclohexanone 83 appended the butenolide, and a few additional steps provided (-)-gymnodimine (1). A diastereomer of the natural product was also synthesized, C4-epi-gymnodimine (90), derived from the vinylogous Mukaiyama aldol addition.
