Abstract
Herein we present the synthesis of the anhydrophytosphingosine jaspine B and three of its stereoisomers using a carbohydrate-derived alkoxyallene in order to obtain the products in enantiopure form. Key step of the reaction sequence is the addition of the lithiated alkoxyallene to pentadecanal, setting the configuration at the later C-2 of the ring system. This reaction step proceeds with moderate selectivity and therefore leads to a stereodivergent approach to the natural product and its enantiomer. The gold-catalyzed 5-endo-cyclization affords the corresponding dihydrofurans, which after separation, azidation of the enol ether moiety and two subsequent reduction steps give the natural product and its stereoisomers.
Highlights
Jaspine B, known as pachastrissamine (1, Scheme 1), is an anhydrophytosphingosine derivative, isolated 2002 from the marine sponge Pachastrissa sp. by Higa et al [1]
Initial studies examined the feasibility of this planned approach for the generation of the functionalized tetrahydrofuran system
Having established suitable conditions for the construction of the functionalized tetrahydrofuran core we focused our attention on the synthesis of enantiopure jaspine B (1)
Summary
Jaspine B, known as pachastrissamine (1, Scheme 1), is an anhydrophytosphingosine derivative, isolated 2002 from the marine sponge Pachastrissa sp. by Higa et al [1]. A subsequent 5-endo-cyclization of the resulting allenyl alcohols leads to a mixture of diastereomeric dihydrofurans, which can be separated by HPLC (only the (S)enantiomer is depicted). This allows the synthesis of the natural product and its enantiomer by functionalization of both diastereomers.
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