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.
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.