Beilstein J. Org. Chem.2017,13, 2326–2331, doi:10.3762/bjoc.13.229
biosynthetic precursors/metabolites differing by the ring A fragment. The protocol is based on the use of readily available phytohormones of this class bearing a 2α,3α-diol moiety (epibrassinolide or epicastasterone) as starting materials. The required functionalities (Δ2-, 2α,3α- and 2β,3β-epoxy-, 2α,3β-, 2β
,3α-, and 2β,3β-dihydroxy-, 3-keto-, 3α- and 3β-hydroxy-, 2α-hydroxy-3-keto-) were synthesized from 2α,3α-diols in a few simple steps (Corey–Winter reaction, epoxidation, oxidation, hydride reduction, etc.).
Keywords: biosynthetic precursors; brassinosteroids; diols; epibrassinolide; epicastasterone
; metabolites; Introduction
The group of steroid plant hormones called brassinosteroids (BS) currently comprises about 70 compounds [1]. It is generally accepted that only few of them (such as brassinolide, castasterone, epibrassinolide, etc.), possessing 2α,3α-, (22R,23R)-diol groups, B-lactone, and 6-ketone
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Graphical Abstract
Scheme 1:
Structural features of epicastasterone (1), epibrassinolide (2) and A-ring units 3–12 of BS biosynt...