410077-39-3Relevant academic research and scientific papers
Spongipyran synthetic studies. Evolution of a scalable total synthesis of (+)-spongistatin 1
Smith III, Amos B.,Sfouggatakis, Chris,Risatti, Christina A.,Sperry, Jeffrey B.,Zhu, Wenyu,Doughty, Victoria A.,Tomioka, Takashi,Gotchev, Dimitar B.,Bennett, Clay S.,Sakamoto, Satoshi,Atasoylu, Onur,Shirakami, Shohei,Bauer, David,Takeuchi, Makoto,Koyanagi, Jyunichi,Sakamoto, Yasuharu
supporting information; experimental part, p. 6489 - 6509 (2011/02/25)
Three syntheses of the architecturally complex, cytotoxic marine macrolide (+)-spongistatin 1 (1) are reported. Highlights of the first-generation synthesis include: use of a dithiane multicomponent linchpin coupling tactic for construction of the AB and CD spiroketals, and their union via a highly selective Evans boron-mediated aldol reaction en route to an ABCD aldehyde; introduction of the C(44)-C(51) side chain via a Lewis acid-mediated ring opening of a glucal epoxide with an allylstannane to assemble the EF subunit; and final fragment union via Wittig coupling of the ABCD and EF subunits to form the C(28)-C(29) olefin, followed by regioselective Yamaguchi macrolactonization and global deprotection. The second- and third-generation syntheses, designed with the goal of accessing 1 g of (+)-spongistatin 1 (1), maintain both the first-generation strategy for the ABCD aldehyde and final fragment union, while incorporating two more efficient approaches for construction of the EF Wittig salt. The latter combine the original chelation-controlled dithiane union of the E- and F-ring progenitors with application of a highly efficient cyanohydrin alkylation to append the F-ring side chain, in conjunction with two independent tactics to access the F-ring pyran. The first F-ring synthesis showcases a Petasis-Ferrier union/rearrangement protocol to access tetrahydropyrans, permitting the preparation of 750 mg of the EF Wittig salt, which in turn was converted to 80 mg of (+)-spongistatin 1, while the second F-ring strategy, incorporates an organocatalytic aldol reaction as the key construct, permitting completion of 1.009 g of totally synthetic (+)-spongistatin 1 (1). A brief analysis of the three syntheses alongside our earlier synthesis of (+)-spongistatin 2 is also presented.
Spongistatin synthetic studies. An efficient, second-generation construction of an advanced ABCD intermediate
Smith III, Amos B.,Doughty, Victoria A.,Sfouggatakis, Chris,Bennett, Clay S.,Koyanagi, Jyunichi,Takeuchi, Makoto
, p. 783 - 786 (2007/10/03)
(formula presented) A short, efficient, and stereocontrolled synthesis of (-)-4, an advanced ABCD subunit of the spongistatins, has been achieved. Central to the synthetic strategy is the multicomponent linchpin union of silyl dithianes with epoxides to access both the AB and CD fragments. Fragment coupling was then achieved via an efficient stereoselective aldol reaction. The linear sequence required 22 steps and proceeded in 4.0% overall yield.
