Synthesis of (+)-obtusenyne.
An enantioselective synthesis of the halogenated medium-ring ether natural product (+)-obtusenyne is reported which uses the ring expansion of a seven-membered ketene acetal by means of a Claisen rearrangement to construct the core nine-membered oxygen heterocycle. The trans substituents across the ether linkage were established by using a transition-metal-catalyzed intramolecular hydrosilation reaction of an exo-cyclic enol ether. In addition, a formal synthesis of ent-obtusenyne from 2-deoxy-D-ribose is reported. A number of interesting points regarding the chemistry of medium-ring oxygen heterocycles are highlighted.
Mak
S Y Frankie
SY
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Curtis
Neil R
NR
Payne
Andrew N
AN
Congreve
Miles S
MS
Wildsmith
Andrew J
AJ
Francis
Craig L
CL
Davies
John E
JE
Pascu
Sofia I
SI
Burton
Jonathan W
JW
Holmes
Andrew B
AB
D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism
D000480:Alkynes; D004988:Ethers, Cyclic; C476642:obtusenyne