Chemistry of unique chiral olefins .3. Synthesis and absolute stereochemistry of trans- and cis-1,1',2,2',3,3',4,4'-octahydro-3,3'-dimethyl-4,4'-biphenanthrylidenes
Chemistry of unique chiral olefins .3. Synthesis and absolute stereochemistry of trans- and cis-1,1',2,2',3,3',4,4'-octahydro-3,3'-dimethyl-4,4'-biphenanthrylidenes
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DOI：
10.1021/ja970669e
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发表时间：
1997-08-06
影响因子：
15
通讯作者：
Feringa, BL
中科院分区：
文献类型：
--
作者：
Harada, N;Koumura, N;Feringa, BL
以P)-(E)-(-)-1，1‘，2，2’，3，3‘，4，4’-octahydro-3，3‘-dimethyl-4，4’-biphenanthrylidene(11)为起始原料，以光学纯的形式合成了具有两个甲基作为绝对立体化学内参照的独特的手性烯烃(3R，3‘R)-(P，3’R)-(P，(3R，4R)-(+)-1，2，3，4-tetrahydro-3-methyl-4-phenanthrenol(3))及其(3R，3‘R)-(P，P)-(Z)-异构体(4)，用新型手性助剂二氯邻苯二甲酸酰胺(14)拆分得到。通过对酯(-)-16b和(-)-3本身的X射线晶体分析，确定了手性反式-二甲基烯烃(-)-3的绝对立体化学。以反式-烯烃(-)-3为原料，通过光化学反应制备了光学纯的顺式-二甲基烯-4。这些手性二甲基烯烃的CD光谱在B-1(B)过渡区表现出很强的Cotton效应，反映了它们的强扭曲的pi电子体系。(3R，3‘R)-(P，P)-(E)-((-))-3与(M，M)-(E)-1，1’，2，2‘，3，3’，4，4‘-octahydro-4，4’-biphenanthrylidene(1))的CD谱形状相似，符号相反。因此，用实验方法建立了理论上确定的(M，M)-(E)-1的绝对立体化学。(3R，3‘R)-(P，P)-(Z)-4的CD谱也与(M，M)-(Z)-1，1’，2，2‘，3，3’，4，4‘-octahydro-4，4’-biphenanthrylidene(2))的CD谱形状相似，符号相反。证实了理论上确定的(M，M)-(Z)-2的绝对立体化学。
Unique chiral olefins with two methyl groups as the internal reference of absolute stereochemistry, (3R,3'R)-(P,P)-(E)-(-)-1,1',2,2',3,3',4,4'-octahydro-3,3'-dimethyl-4,4'-biphenanthrylidene (3) and its (3R,3'R)-(P,P)-(Z)-isomer (4), were synthesized in optically pure form starting from (3R,4R)-(+)-1,2,3,4-tetrahydro-3-methyl-4-phenanthrenol (11), which was obtained by the enantioresolution using a novel chiral auxiliary of dichlorophthalic acid amide (14). The absolute stereochemistry of chiral trans-dimethyl olefin (-)-3 was determined by the X-ray crystallographic analyses of ester (-)-16b and (-)-3 itself. Optically pure cis-dimethyl olefin 4 was prepared by photochemical reaction of trans-olefin (-)-3. The CD spectra of these chiral dimethyl olefins exhibit very intense Cotton effects in the B-1(b) transition region reflecting their strongly twisted pi-electron systems. The CD spectrum of (3R,3'R)-(P,P)-(E)-((-))-3 is almost similar in shape but opposite in sign to that of (M,M)-(E)-1,1',2,2',3,3',4,4'-octahydro-4,4'-biphenanthrylidene (1). Therefore, the absolute stereochemistry of (M,M)-(E)-1 previously theoretically determined was established in an experimental manner. The CD spectrum of (3R,3'R)-(P,P)-(Z)-4 is also almost similar in shape but opposite in sign to that of (M,M)-(Z)-1,1',2,2',3,3',4,4'-octahydro-4,4'-biphenanthrylidene (2). The absolute stereochemistry of (M,M)-(Z)-2 theoretically determined was corroborated.