Synthesis of a key intermediate for corossolin using hydrolytic kinetic resolution of epoxides

Parallel Fragment Assembly Strategy Towards Multiple‐Ether Mimicry of Anticancer Annonaceous Acetogenins

“…Appendage of butenolide units onto 24 and 25 to form 26 and 27 involved a three‐step sequence: 1) aldol reaction of 24 and 25 with freshly prepared (2 S )‐ O ‐tetrahydropyranyl ( O ‐THP) lactal, 2) acid‐catalyzed deprotection of the O ‐THP group and in situ lactonization, and 3) elimination of a β‐hydroxy group by treatment with (CF 3 CO) 2 O and Et 3 N. Regioselective epoxidation of 26 and 27 was achieved by treatment with m CPBA to give 28 and 29 in 86 % yield. The hydrolytic kinetic resolution of Jacobsen and co‐workers was applied to resolve the terminal epoxides 16b. This reaction was performed in the presence of an ( S , S )‐salen–Co(OAc) complex (0.5 mol %) and H 2 O (0.55 equiv) to yield 30 and 31 (43 %) and diols 32 and 33 (50 %) at 4 °C.…”

Recent developments in the synthesis of furan-2(5H)-ones

“…The same group have reported the use of Jacobsen's HKR (Hydrolytic Kinetic Resolution) in the preparation of a highly enantiomerically-enriched Corossoline intermediate. 54 Thus, epoxyfuranone (96) was prepared by the previouslyemployed synthetic pathway 55 involving aldol-like reaction of the enolate derived from methyl undec-10-enoate with protected lactaldehyde. The racemic mixture resulting was hydrolytically-resolved by reaction with a sub-stoichiometric amount of (R,R)-salen-Co(OAc).…”

Saturated oxygen heterocycles

“…8 This type of reaction is second order in Co(salen) complex 4, and so Jacobsen and co-workers have been able to design dimeric catalysts which are able to catalyse the azide ring-opening of epoxides at catalytic concentrations an order of magnitude lower than with monomeric catalysts. 9 This approach has been used to prepare a key intermediate for the synthesis of the annonaceous acetogenin corossilin, 10 and to prepare long chain alkyl epoxides. 11 More conventional enzymic epoxide resolutions have also been reported.…”