The sclerophytin A adventure.
The structural designation A originally made by Sharma and Alam to sclerophytin A was considered to be ambiguous and so notably strained relative to B that the latter was targeted for de novo synthesis (Scheme 1). Our two successful routes began with (5S)-(d-menthyloxy)-2(5H)-furanone and involved the application of cycloaddition, Claisen ring expansion, transannular oxymercuration, and 1,2-carbonyl transposition tactics to arrive at B. It was immediately apparent from polarity considerations and spectroscopic data that the antileukemic marine metabolite in question was in need of more deep-seated structural revision. Following close re-examination of an acquired authentic sample by advanced NMR techniques, the strong inference was made that sclerophytin A actually lacked a second oxygen bridge and was in reality the triol C. This conclusion was unequivocally confirmed by diverting an advanced intermediate generated earlier into a short sequence beginning with regiocontrolled dihydroxylation and terminating with configurational inversion at the secondary carbinol center. The status of other members of this series is also presented.
Paquette
L A
LA
Evans Chemical Laboratories, The Ohio State University, Columbus 43210, USA. paquette.1@osu.edu
D000818:Animals; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D008386:Marine Biology; D015394:Molecular Structure; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis / Q000737:chemistry
D001952:Bridged-Ring Compounds; D005663:Furans; D013729:Terpenes; C412667:sclerophytin A; C412668:sclerophytin B