The C-15/C-27 segment of venturicidine contains a 1,3,5,n-anti-methylated alkyl chain, which resembles syndiotactic polypropylene and should therefore favor an extended conformation. A synthetic scheme is presented, by which such structures are generated in a cycle of four steps per three stereogenic centers. This allowed the synthesis of the above mentioned venturicidine fragment in 15 steps from propionaldehyde.
Synthesis of the C22−C26 Tetrahydropyran Segment of Phorboxazole by a Stereoselective Prins Cyclization
作者:Scott D. Rychnovsky、Christian R. Thomas
DOI:10.1021/ol005646a
日期:2000.5.1
see text] Tetrahydropyran rings are found in many complex natural products, and the segment-coupling Prins cyclization is an effective strategy for their synthesis. We report a four-step, stereoselectivesynthesis of the C20-C27 tetrahydropyran segment of phorboxazole. The key step is a Prins cyclization induced by catalytic BF3.OEt2.
Rapid stereocontrolled assembly of the fully substituted C-aryl glycoside of kendomycin with a Prins cyclization: a formal synthesis
作者:Kevin B. Bahnck、Scott D. Rychnovsky
DOI:10.1039/b602937j
日期:——
Prins cyclization using an electron-rich benzaldehyde and a homoallylic alcohol efficiently delivered the fully substituted C-aryl tetrahydropyranoside of kendomycin.
Stereoselective Synthesis of Alcohols, L. Stereoselective Synthesis of a C-15/C-27 Segment of the Venturicidines
作者:Reinhard W. Hoffmann、Ulrike Rolle、Richard Göttlich
DOI:10.1002/jlac.199619961104
日期:1996.11
Chain extension of an aldehyde by two “propionate” units has been attained by stereoselective allylboration with the chiral 1-methylbutenyl boronate 3 to give, e.g., the homoallylic alcohol 6, followed by a regioselective hydroboration/carbonylation procedure to give, e.g., the epimeric aldehydes 8. The latter were converted into the lactols 10, which equilibrated to the desired epimer. The lactols