253662-80-5Relevant academic research and scientific papers
Total synthesis of polycavernoside A, a lethal toxin of the red alga Polycavernosa tsudai
Blakemore, Paul R.,Browder, Cindy C.,Hong, Jian,Lincoln, Christopher M.,Nagornyy, Pavel A.,Robarge, Lonnie A.,Wardrop, Duncan J.,White, James D.
, p. 5449 - 5460 (2007/10/03)
Two approaches to the synthesis of the aglycon 120 of polycavernoside A (1) were developed, only one of which was completed. The successful "second-generation" route assembled the aglycon seco acids 102 and 106 via Nozaki-Hiyama-Kishi coupling of aldehyde 70, prepared from methyl (S)-3-hydroxy-2-methylpropionate (72) and (S)-pantolactone (73), with vinyl bromide 71. The latter was obtained from a sequence which commenced from the silyl ether 24 of 3-hydroxypropionaldehyde and entailed cyclization of (Z)-ζ-hydroxy-α,β-unsaturated ester 82. Regioselective Yamaguchi lactonization of trihydroxycarboxylic acids 102 and 106 and subsequent functional-group adjustments led to macrolactone 120, to which the fucopyranosylxylopyranoside moiety was attached. Stille coupling of the glycosidated aglycon 128 with dienylstannane 129 furnished polycavernoside A in a synthesis for which the longest linear sequence was 25 steps. The overall yield to lactone 120 was 4.7%.
An effective method for the preparation of chiral polyoxy 8-membered ring enone corresponding to the B ring of taxol
Shiina,Shibata,Ibuka,Imai,Mukaiyama
, p. 113 - 122 (2007/10/03)
An effective method for the preparation of 8-membered ring enone, (4S,5R,7R,8R)-4,8-bis(benzyloxy)-7-(t-butyldimethylsiloxy)-5- (4-methoxybenzyloxy)-2,6,6-trimethylcyclooct-2-enone (1), in sufficient quantities was developed. Optically active trioxy aldehyde, (3R,4S)-4-benzyloxy-5-(t-butyldimethylsiloxy)-3-(4-methoxybenzyloxy)- 2,2-dimethylpentanal (3), was prepared first by diastereoselective dihydroxylation of (2R,4S)-2-(4-methoxyphenyl)-5,5-dimethyl-4-vinyl-1,3-dioxane derived from D-pantolactone. Next, 8-chloro-7-oxoaldehyde, (2R,3R,5R,6R)-2,6-bis(benzyloxy)-5-(t-butyldimethylsiloxy)-8-chloro-3- (4-methoxybenzyloxy)-4,4-dimethyl-7-oxononanal (30), was newly synthesized by the following reactions: i) MgBr2·OEt2-mediated diastereoselective aldol reaction of the aldehyde 3 with (Z)-2-benzyloxy-1-methoxy-1-(trimethylsiloxy)ethene and ii) reaction of methyl (2R,3R,5R,6S)-2,6-bis(benzyloxy)-3,7-bis(t-butyldimethylsiloxy)-5- (4-methoxybenzyloxy)-4,4-dimethylheptanoate with 1,1-dichloroethyllithium, followed by successive reductive dehalogenation of thus formed 1,1-dichloroethyl ketone with 1,1-dichloroethyllithium. Then, the chiral 8-chloro-7-oxoaldehyde 30 was converted to the 8-membered ring enone 1 by SmI2-mediated aldol cyclization.
An effective method for the preparation of optically active polyoxy 8-membered ring enone corresponding to the B ring of taxol
Shiina, Isamu,Shibata, Jun,Imai, Yumiko,Ibuka, Ryoutarou,Fujisawa, Hidehiko,Hachiya, Iwao,Mukaiyama, Teruaki
, p. 1145 - 1146 (2007/10/03)
An effective method for the preparation of 8-membered ring enone 1 in sufficient quantities was developed. First, optically active trialkoxyaldehyde 3 was prepared by diastereoselective dihydroxylation of olefin 7 derived from D-pantolactone. Secondly, 8-
