Potentially scalable total synthesis of reblastatin was achieved based on Panek’s previous study. Novel
and convenient synthetic routes were developed for the known C8eC20 and C1eC7 coupling partners.
The challenging C8eC20 fragment was prepared from TBS protected (S)-5-(hydroxymethyl)dihydrofuran-2(3H)-one (6) in nine steps (20% overall yield), and the C1eC7 fragment was synthesized from
commercially available 3,4,6-tri-O-acetyl-D-glucal (9) in eight steps (35% overall yield). On a larger scale,
Panek’s eight-step assembly of the target molecule from the two partners was also slightly modified,
giving 45 mg reblastatin (19% overall yield) in thefirst batch synthesis. Notable feature of our study is the
settlement of the C14 chirality through a diastereoselectivea-alkylation of6followed by a three-step full
reduction of the lactone carboxyl, making vastly available6a universally applicable C11eC14 synthon for
benzenoid/benzoquinone ansamycins.
Potentially scalable total synthesis of reblastatin was achieved based on Panek’s previous study. Noveland convenient synthetic routes were developed for the known C8eC20 and C1eC7 coupling partners.The challenging C8eC20 fragment was prepared from TBS protected (S)-5-(hydroxymethyl)dihydrofuran-2(3H)-one (6) in nine steps (20% overall yield), and the C1eC7 fragment was synthesized fromcommercially available 3,4,6-tri-O-acetyl-D-glucal (9) in eight steps (35% overall yield). On a larger scale,Panek’s eight-step assembly of the target molecule from the two partners was also slightly modified,giving 45 mg reblastatin (19% overall yield) in thefirst batch synthesis. Notable feature of our study is thesettlement of the C14 chirality through a diastereoselectivea-alkylation of6followed by a three-step fullreduction of the lactone carboxyl, making vastly available6a universally applicable C11eC14 synthon forbenzenoid/benzoquinone ansamycins.
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