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.
The C15–C27 portion of venturicidin X was prepared using substitution reactions of alkyl trifluoromethanesulfonates with a vinylmetal compound followed by homogeneous hydrogenation. Together with our previous synthesis of the C1–C14 portion of venturicidin X, a formal totalsynthesis of venturicidin X was completed.
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
Synthesis of C15–C27 segment of venturicidine X by utilizing desymmetrization protocol
作者:J.S. Yadav、Sk. Samad Hossain、Debendra K. Mohapatra
DOI:10.1016/j.tetlet.2010.05.148
日期:2010.8
We have achieved the synthesis of C15-C27 fragment of venturicidine X using desymmetrization protocol, substrate-controlled Grignard reaction, Barton-McCombie reaction, Sharpless epoxidation, and TBSOTf-mediated rearrangement to produce the aldol product through a non-aldol route as the key step following 23 longest linear sequences with 6.4% overall yield starting from a known intermediate 11. (C) 2010 Elsevier Ltd. All rights reserved.