Total synthesis of (-)-bitungolide F and determination of its absolute stereochemistry.
A highly convergent total synthesis of bitungolide F leading to the assignment of its absolute stereochemistry is described. The key steps include a Horner-Wadsworth-Emmons olefination to construct the C7-C8 bond, a Wittig reaction to introduce the conjugate E,E-olefinic moiety in the molecule, and finally a ring-closing metathesis reaction to construct the six-membered alpha,beta-unsaturated delta-lactone of the molecule. Modified Evans's syn-aldol reaction, using Crimmins's protocol, was used to install the stereochemistries at the C4 and C5 centers. The stereochemistry at C9 was introduced by means of hydroxy-directed reduction of the C9 keto using Evans's protocol.
Ghosh
Subhash
S
Indian Institute of Chemical Technology, Hyderabad 500 007, India. subhash@iict.res.in
Kumar
Soma Uday
SU
Shashidhar
J
J
D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism
D000475:Alkenes; D011753:Pyrones; C528466:bitungolide F