MODIFICATION OF WITTIG REACTION TO PERMIT STEREOSPECIFIC SYNTHESIS OF CERTAIN TRISUBSTITUTED OLEFINS . STEREOSPECIFIC SYNTHESIS OF ALPHA-SANTALOL
MODIFICATION OF WITTIG REACTION TO PERMIT STEREOSPECIFIC SYNTHESIS OF CERTAIN TRISUBSTITUTED OLEFINS . STEREOSPECIFIC SYNTHESIS OF ALPHA-SANTALOL
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DOI：
10.1021/ja00704a052
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发表时间：
1970-01-01
影响因子：
15
通讯作者：
YAMAMOTO, H
中科院分区：
文献类型：
--
作者：
COREY, EJ;YAMAMOTO, H
(1)M. Schlosser和K. F. Christmann，Angew.化学实习生。Ed. Engl，5，126（1966）; Ann. Chem.，708，1（1967）。Wittig-Schlosser合成不需要叔丁醇钾-叔丁醇试剂。2这一发现表明，中间体β-氧化膦叶立德（β-膦基甜菜碱与苯基锂反应的明显产物）能够有规立构质子化生成苏型甜菜碱，后者是最终生成反式-1，2-二取代乙烯的前体。似乎合乎逻辑的是，预期只有一种同分异构的甜菜碱可能通过亲电体而不是质子供体与α-氧化膦叶立德的反应特异性地形成，并且由此可能获得一种有用的立体特异性路线以获得三取代烯烃。本文描述了这种合成过程的实现。[3]发表迄今为止所获得的结果是由于出现了一个说明，该说明描述了一种氧化膦叶立德[4]的反应研究，它与目前的工作部分重叠。上述方法可立体定向合成1a、3、51 b、35和2a、3a、e型三取代烯烃，但不能合成2b型三取代烯烃。我们将首先描述一种新的合成方法，
(1) M. Schlosser and K. F. Christmann, Angew. Chem. Intern. Ed. Engl, 5, 126 (1966); Ann. Chem., 708, 1 (1967). the potassium z-butoxide-z-butyl alcohol reagent is not required for the Wittig-Schlosser synthesis. 2 Thisfinding implied that the intermediate ß-oxido phosphonium ylide (the obvious product of the reaction of a phos-phorus betaine with phenyllithium) is capable of stereospecific protonation to form the threo betaine which is the precursor of the trans-1, 2-disubstituted ethylene finally formed. It seemed logical to expect that only one of the isomeric betaines might be formed specifically by the reaction of electrophiles other than proton donors with ß-oxido phosphonium ylides and that a useful stereospecific route to trisubstituted olefins might thereby become available. This communication describes the realization of such a synthetic process. 3 Publication of the results which have been obtained thus far is prompted bythe appearance of a note describing a study of reactions of ß-oxide phosphonium ylides4 which par-tially overlaps the present work. Methods which have been described previously per-mit the stereospecific synthesis of trisubstituted olefins of types la, 3· 5 lb, 35 andalso 2a, 3a, e but not of type 2b. We shall first describe a new approach to the synthesis of