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Concise synthesis of the bryostatin A-ring via consecutive C-C bond forming transfer hydrogenations
1University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, Texas 78712, USA.
Abstract:
Under the conditions of C-C bond forming transfer hydrogenation, 1,3-propanediol 1 engages in double asymmetric carbonyl allylation to furnish the C(2)-symmetric diol 2. Double ozonolysis of 2 followed by TBS protection delivers aldehyde 3, which is subject to catalyst directed carbonyl reverse prenylation via transfer hydrogenation to deliver neopentyl alcohol 4 and, ultimately, the bryostatin A-ring 7. Through use of two consecutive C-C bond forming transfer hydrogenations, the Evans' bryostatin A-ring 7 is prepared in less than half the manipulations previously reported.
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