Jackpot: Two for one! Concise and highly convergent syntheses of the immunosuppressive agent FR252921 and the related antimicrobial natural product pseudotrienic acid B were achieved from one common intermediate by using optically active titanium complexes to control the configuration of the stereogenic centers, a highly stereo‐ and regioselective cross‐metathesis to generate the triene moieties, and
A concise and highly convergent synthesis of the promisingimmunosuppressantFR252921 was achieved by using optically active titanium complexes to control the configuration of the three stereogenic centers.
Synthesis of Two Subunits of the Macrolide Domain of the Immunosuppressive Agent Sanglifehrin A and Assembly of a Macrolactone Precursor. Application of Masamune <i>anti</i>-Aldol Condensation
作者:Khomson Suttisintong、James D. White
DOI:10.1021/jo5027595
日期:2015.2.20
Asymmetric anti-aldol coupling of a norephedrine-derived ester with an a-chiral aldehyde was used to synthesize a carboxylic acid representing the C13-C19 segment of the macrocyclic domain present in the immunosuppressive agent sanglifehrin A. Felkin addition set configuration at the C14-C17 stereotetrad in this unit in which hydroxyl functions at C15 and C17 were masked as an internal ketal. The carboxyl group of this segment was coupled to the N-terminus of the tripeptide portion (C1-N12) of sanglifehrin A macrolactone to assemble the C1-C19 domain. Synthesis of the C20-C25 subunit of sanglifehrin A containing a (23S) alcohol was completed via asymmetric allylation of (E)-3-iodo-2-methylprop-2-enal followed by oxidative cleavage of the terminal vinyl appendage and a Takai olefination with pinacol dichloromethylboronate. Esterification of this alcohol with a C1-C19 carboxylic acid furnished an open C1-C25 macrolactone precursor, but this substance failed to undergo macrocyclization via intramolecular SuzukiMiyaura coupling.