110935-52-9Relevant academic research and scientific papers
Total syntheses of (+)- and (-)-didemnenones A and B. Antiselectivity in the intramolecular carbomercuration reaction
Forsyth, Craig J.,Clardy, Jon
, p. 3497 - 3505 (2007/10/02)
Total synthese of the title compounds were achieved in 11 steps and ca. 7% overall yield from the chiral synthon 10. In conjuction with previous chiroptical stuudies, this work allowed the assignment of absolute configurations to didemnenones A-D (1-4, respectively), a series of cytotoxic cyclopentanoid marine natural products isolated from the tunicates Trididemnum cf. cyanophorum and Didemnum voeltzkowi. Thus, 1 and 2 were shown to have the 2R,6R configuration; 3 was shown to have the 2S,6S, and 4, most plausibly, the 2S,6R configurations. Featured in the syntheses are an efficient 1,3 chirality transfer to establish the C2 configuration, one-pot mercuric chloride induced intramolecular cyclization/iodination reactions of an ε-alkynyl silyl enol ether to form a cis-6-oxabicyclo[3.3.0]oct-3-en-2-one system bearing an exocyclic C8-vinyl iodide and an installation of the C11 oxidation level and diene moiety by sequential SeO2/t-BuOOH oxidation and Pd-mediated vinyl cross-coupling with n-Bu3SnCHCH2. In examining the intramolecular carbomercurations of cyclopentenone silyl enol ethers bearing β-(2-propynyloxy) side chains, an apparently exclusive and unexpected antiselectivity was revealed.
A New Synthesis of (+)-Didemnenones A and B
Sugahara, Tsutomu,Ohike, Tomoko,Soejima, Motohiro,Takano, Seiichi
, p. 1824 - 1826 (2007/10/02)
(+)-Didemnenones A (1) and B (2), unique and biologically active C11-cyclopentenone metabolites from a tunicate, were synthesized from the optically active lactone (4).
