Stereoselective Synthesis of 2,6-<i>syn</i>-Dimethyl-tetrahydropyran Derivatives, Important Segments of Marine Polycyclic Ethers, by Unique Insertion of the Methyl Group
have a 1′-mesyloxy group at the C2-side chain, with Me3Al effected stereoselective insertion of a methyl group at the C2-position to give 2,6-syn-dimethyl-tetrahydropyran derivatives. This reaction proceeds via removal of the mesyloxy group, 1,2-hydride shift, and stereoselective insertion of a methyl group into the resulting oxonium ion.
Synthetic Studies on Maitotoxin. 3. Stereoselective Synthesis of the BCDE-Ring System
作者:Masanori Satoh、Hiroyuki Koshino、Tadashi Nakata
DOI:10.1021/ol8002699
日期:2008.5.1
The stereoselectivesynthesis of the BCDE-ring system of maitotoxin has been accomplished through a two-directional strategy for the construction of polycyclic ether. The key reactions involve SmI 2-induced double cyclization of a beta-alkoxyacrylate and a double dihydroxylation for construction of the B- and E-rings.