Absolute structures and conformations of the spongian diterpenes spongia-13(16), 14-dien-3-one, epispongiadiol and spongiadiol
Absolute structures and conformations of the spongian diterpenes spongia-13(16), 14-dien-3-one, epispongiadiol and spongiadiol
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DOI：
10.1107/s0108270109008816
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发表时间：
2009-04-01
影响因子：
0.8
通讯作者：
Bernhardt, Paul V.
中科院分区：
文献类型：
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作者：
Yong, Ken W. L.;Garson, Mary J.;Bernhardt, Paul V.
海绵-13（16），14-二烯-3-酮[系统名称：（3bR，5aR，9aR，9 bR）-3b，6，6，9a-四甲基-4，5，5a，6，8，9，9a，9 b，10，11-十氢菲并[1，2-c]呋喃-7（3bH）-酮]，C20 H28 O2，（I），epispongiadiol [系统名称：（3bR，5aR，6S，7 R，9aR，9 bR）-7-羟基-6-羟甲基-3b，6，9a-三甲基-3b，5，5a，6，7，9，9a，9 b，10，11-十氢菲并[1，2-c]呋喃-8（4 H）-酮]、C20 H28 O 4（II）和海绵二醇[系统名称：（3bR，5aR，6S，7S，9aR，9 bR）-7-羟基-6-羟甲基-3b，6，9a-三甲基-3b，5，5a，6，7，9，9a，9 b，10，11-十氢菲并[1，2-c]呋喃-8（4 H）-酮]，C20 H28 O 4，（III），通过分析在130 K下用Cu K α辐射收集的反常色散数据进行归属。化合物（II）和（III）是差向异构体。（II）的环己酮环（A）上的赤道3-羟基相对于4-羟甲基是顺式的，导致椅式构象。相比之下，异构体（III），其中3-羟基是反的4-羟甲基，是构象无序之间的主要椅子构象，其中OH基团是轴向和次要的船构象，其中它是赤道。在化合物（I）中，羰基存在于3位并且环A采用扭曲船构象。
The absolute configurations of spongia-13(16), 14-dien-3-one [systematic name: (3bR,5aR,9aR,9bR)-3b,6,6,9a-tetramethyl-4,5,5a,6,8,9,9a,9b,10,11-decahydrophenanthro[1,2-c]furan-7(3bH)-one], C20H28O2, (I), epispongiadiol [systematic name: (3bR,5aR,6S,7R,9aR,9bR)-7-hydroxy-6-hydroxymethyl-3b,6,9a-trimethyl-3b, 5,5a,6,7,9,9a,9b,10,11-decahydrophenanthro[1,2-c]furan-8(4H)-one], C20H28O4, (II), and spongiadiol [systematic name: (3bR,5aR,6S,7S,9aR,9bR)-7-hydroxy-6-hydroxymethyl-3b,6,9a- trimethyl-3b,5,5a,6,7,9,9a,9b,10,11-decahydrophenanthro[1,2-c] furan-8(4H)-one], C20H28O4, (III), were assigned by analysis of anomalous dispersion data collected at 130 K with Cu K alpha radiation. Compounds (II) and (III) are epimers. The equatorial 3-hydroxyl group on the cyclohexanone ring (A) of (II) is syn with respect to the 4-hydroxymethyl group, leading to a chair conformation. In contrast, isomer (III), where the 3-hydroxyl group is anti to the 4-hydroxymethyl group, is conformationally disordered between a major chair conformer where the OH group is axial and a minor boat conformer where it is equatorial. In compound (I), a carbonyl group is present at position 3 and ring A adopts a distorted-boat conformation.