Marine polycyclic ethers

Synthetic study on marine polycyclic ethers and total synthesis of hemibreve-toxin B 98YGK940. 

Sasaki M (2006) Recent Advances in Total Synthesis of Marine Polycyclic Ethers. 5 149-178 Satake M (2006) Marine Polyether Compounds. 5 21-51 Shan R, see Maiti SN (2006) 2 207-246... 

Nakata utilised the Sml2-mediated Barbier-type cyclisation of a primary iodide with an ester as part of a convergent synthesis of trans-fused 6,6,6,6-tetracyclic ethers, which are typically found in marine polycyclic ethers.62 Treatment of iodide 50 with excess Sml2 in the presence of 1 mol% of Nil2 led to the smooth formation of intermediate hemiacetal 51, which was dehydrated to give dihy-dropyran 52 that was then further elaborated to give tetracycle 53 (Scheme 7.23).62... 

Brevetoxin-B (PbTx-2, 1) is the first member of the marine polycyclic ethers to have been stmc-turally elucidated and one of the most potent neurotoxins (Lin et al. 1989). Its highly complex... 

Kadota, I., and Yamamoto, Y. 2005. Synthetic Strategies of Marine Polycyclic Ethers via Intramolecular Allylations Linear and Convergent Approaches. Acc Chem Res 38, 423-432. 

In place of the aryl halide or alkenyl halide, the corresponding phosphate or triflate have been employed for the above cross-coupling reaction (O Scheme 71) [102]. These substrates were easily prepared from the corresponding lactone. The reaction of alkenyl phosphate or triflate has frequently been employed in the synthesis of marine polycyclic ethers such as brevetoxin... 

The first total synthesis of the marine polycyclic ether toxin (-)-gambierol was accomplished in the laboratory of M. Sasaki. The introduction of the a,(3-unsaturation into the seven-membered H ring of the FGH tricyclic subunit proved to be problematic, because both the conventional selenium-based method and the Nicolaou oxidation with IBX failed. However, when the seven-membered ketone was treated with LiHMDS in the presence of TMSCI and EtsN, the corresponding silyl enol ether was formed, which was oxidized under Saegusa conditions to give the desired cyclic enone in high yield. Because of the small scale of the reaction, a large excess of Pd(OAc)2 was used in acetonitrile so the presence of a co-oxidant was not necessary. 

Total synthesis of gambierol, a marine polycyclic ether 03YGK742. 

Kadota, I. and Yamamoto, Y, Synthetic strategies of marine polycyclic ethers via intramolecular allylations Linear and convergent approaches, Acc. Chem. Res., 38, 423, 2005. 

Synthetic studies of marine polycyclic ether ciguatoxins 06Y418. 

Total synthesis of marine polycyclic ethers 05CRV4314. 

In the total synthesis of (-)-gambierol, a marine polycyclic ether toxin, by two groups [28,29], the sensitive terminal (Z, Z)-triene side chain in 53 was constructed as a crucial step by stereoselective coupling of (Z)-alkenyl iodide 51 with (Z)-l,4-pentadienylstannane 52 in DMSO to afford 53 in 72% yield without isomerization of the triene system. Pd2(dba)3 and Cul as catalysts and TFP (1-3) as a ligand were used [29]. Similar coupling using the less reactive alkenyl bromide provided 53 in 43 % yield [28]. 

Sasaki M (2006) Recent Advances in Total Synthesis of Marine Polycyclic Ethers. 5 149-178... 

Recent Advances in Total Synthesis of Marine Polycyclic Ethers... 

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