Anti aldol selectivity in a synthetic approach to the C1-C12 fragment of the tedanolides.
نویسندگان
چکیده
In a synthetic approach to the completely protected C1-C12 fragment of the macrocyclic cytotoxic agent tedanolide 1, we carried out the tin-catalyzed Mukaiyama aldol reaction between the 2,3-dialkoxypropanal 5 and the silyl enol ether 6 derived from the ketone 7, which gave, unexpectedly, the anti aldol isomer, rather than the expected syn isomer 4, as the major diastereomer formed.
منابع مشابه
Synthesis of the C1-C12 fragment of the tedanolides. Aldol-non-aldol aldol approach.
The combination of highly stereoselective non-aldol aldol and aldol processes allows the preparation of the completely protected C1-C12 fragment 2 of the novel macrocyclic cytotoxic agent tedanolide 1.
متن کاملSynthesis of a fully functionalized protected C1-C11 fragment for the synthesis of the tedanolides.
[figure: see text] The use of several non-aldol aldol processes allows one to prepare a fully functionalized and completely protected C1-C11 fragment that should be useful for the total synthesis of the tedanolides.
متن کاملEfficient synthesis of the C(1)-C(11) fragment of the tedanolides. The nonaldol aldol process in synthesis.
[reaction: see text] The nonaldol aldol process developed in our laboratories has been applied to the synthesis of a C(1)-C(11) fragment 22 of the novel macrocyclic cytotoxic agents tedanolide and 13-deoxytedanolide 1 and 2. The commercially available hydroxy ester 7 was converted in 24 steps into compound 22 using two nonaldol aldol reactions.
متن کاملSynthetic studies on borrelidin: enantioselective synthesis of the C1-C12 fragment.
[structure: see text] An efficient, enantioselective synthesis of the C1-C12 fragment 2 of borrelidin is presented. Construction of the "skipped" polymethylene chain of 2 was accomplished by iteration of Myers' alkylation, while formation of the C3 stereocenter was achieved by Roush's asymmetric allylboration methodology.
متن کاملEnantioselective synthesis of oasomycin A, part III: fragment assembly and confirmation of structure.
Herein we address the total synthesis of the natural product oasomycin A by assembly of the C1–C12, C13–C28, and C29–C46 subunits, whose syntheses have been described in the preceding Communications. The synthesis plan (Scheme 1) incorporates a speculative late-stage macrolactonization of the linear seco acid precursor to form a 42-membered lactone that upon global deprotection would provide th...
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عنوان ژورنال:
- Organic letters
دوره 10 1 شماره
صفحات -
تاریخ انتشار 2008