A sailboat-shaped 20-membered macrolide, named gibbosolide A, featuring a rare cis-fused 2-methylhexahydro-2H-furo[3,2-b]pyran motif, was obtained from the South China Sea dinoflagellate, Amphidinium gibbosum. Its planar structure and absolute configuration, containing twelve carbon stereocenters, were unambiguously established by extensive NMR investigations, J-based configuration analysis, NOE interactions, ozonolysis of the carbon–carbon double bonds, and the modified Mosher's α-methoxy-α-(trifluoromethyl)phenylacetyl (MTPA) ester method. It displays activation effects on human farnesoid–X–receptor within the concentration range of 200.0 nM to 2.0 μM. Its late-stage cyclization mechanisms are proposed. Most notably, ozonolysis of the carbon–carbon double bonds combined with the modified Mosher's ester method is a useful approach for the unambiguous determination of absolute configurations of hydroxy-bearing carbon stereocenters within the complex macrolide core.

中文翻译：

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Gibbosolide A，一种高度功能化的 20 元大环内酯，具有末端顺式融合的 2-甲基六氢-2H-呋喃 [3,2-b] 吡喃基序：对海洋大环内酯后期环化的见解

从南海甲藻Amphidinium gibbosum中获得了一种帆船形状的20元大环内酯，名为gibbosolide A，具有罕见的顺式稠合2-甲基六氢-2 H-呋喃[3,2- b ]吡喃基序。它的平面结构和绝对构型，包含 12 个碳立体中心，通过广泛的 NMR 研究明确确定，J基于构型分析、NOE 相互作用、碳-碳双键的臭氧分解和改进的 Mosher α-甲氧基-α-(三氟甲基)苯乙酰 (MTPA) 酯方法。它在 200.0 nM 至 2.0 μM 的浓度范围内对人类法尼醇-X-受体显示出激活作用。提出了其后期环化机制。最值得注意的是，碳-碳双键的臭氧分解与改进的 Mosher 酯方法相结合，是明确确定复杂大环内酯核心内含羟基碳立体中心绝对构型的有用方法。