The total synthesis of the marine macrolide bryostatin 2 is described. The synthesis plan relies on aldol and directed reduction steps in order to construct the anti-1,3-diol array present in each of the principal subunits (A, B, and C). These fragments were coupled using a Julia olefination and subsequent sulfone alkylation. A series of functionalization reactions provided a bryopyran seco acid, which was macrolactonized under Yamaguchi conditions. Installation of the two enoate moieties took advantage of asymmetric phosphonate and aldol condensation strategies. Reduction of the C20 ketone and simple protecting group operations then completed the synthesis of bryostatin 2. This flexible approach should provide access to a series of new analogues of this clinically important marine natural product.
Evans, David A.,Carter, Percy H.,Carreira, Erick M.,Charette, André B.,Prunet, Jo?lle A.,Lautens, Mark
p. 7540 - 7552
(2007/10/03)
Asymmetric synthesis of bryostatin 2
The potent bryostatin antitumor agents are currently in phase II clinical trials for the treatment of a variety of forms of cancer. Aldol reactions and directed reductions are among the essential steps for the formation of fragments A-C in the total synthesis of the title compound. Coupling of these fragments by sulfone-based olefination and alkylation reactions was followed by macrocyclization and introduction of the enoate moieties on rings B and C.
Evans, David A.,Carter, Percy H.,Carreira, Erick M.,Prunet, Joelle A.,Charette, Andre B.,Lautens, Mark
p. 2354 - 2359
(2007/10/03)
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