The acid-catalyzed rearrangement of N-(1′,1′-dimethylprop-2′-ynyl)-, N-(1′-methylprop-2′-ynyl)-, and N-(1′-arylprop-2′-ynyl)-2,6-, 2,4,6-, 2,3,5,6-, and 2,3,4,5,6-substituted anilines in mixtures of 1N aqueous H₂SO₄ and ROH such as EtOH, PrOH, BuOH etc., or in CDCl₃ or CCl₄ in the presence of 4 to 9 mol-equiv. trifluoroacetic acid (TFA)has been investigated (cf. Scheme 12-25 and Tables 6 and 7). The rearrangement of N-(3′-X-1′,1′-dimethyl-prop-2′-ynyl)-2,6- and 2,4,6-trimethylanilines (X = Cl, Br, I) in CDCl₃/TFA occurs already at 20° with τ_1/2 of ca. 1 to 5 h to yield the corresponding 6-(1-X-3′-methylbuta-1,2′-dienyl)-2,6-dimethyl- or 2,4,6-trimethylcyclohexa-2,4-dien-1-iminium ions (cf. Scheme 13 and Footnotes 26 and 34) When the 4 position is not substituted, a consecutive [3,3]-sigmatropic rearrangement takes place to yield 2,6-dimethyl-4-(3′-X-1′,1′-dimethylprop-2′-ynyl)anilines (cf. Footnotes 26 and 34). A comparable behavior is exhibited by N-(3′-chloro-1′-phenylprop-2′-ynyl)-2,6-dimethylaniline (45., cf. Table 7). The acid-catalyzed rearrangement of the anilines with a Cl substituent at C(3′) in 1N aqueous H₂SO₄/ROH at 85-95°, in addition, leads to the formation of 7-chlorotricyclo[3.2.1.0^2,7]oct-3-en-8-ones as the result of an intramolecular Diels-Alder reaction of the primarily formed iminium ions followed by hydrolysis of the iminium function (or vice versa; cf. Schemes 13,23, and 25 as well as Table 7). When there is no X substituent at C(1′) of the iminium-ion intermediate, a [1,2]-sigmatropic shift of the allenyl moiety at C(6) occurs in competition to the [3,3]-sigmatropic rearrangement to yield the corresponding 3-allenyl-substituted anilines (cf. Schemes 12,14–18, and 20 as well as Tables 6 and 7). The rearrangement of (−)−(S)-N-(1′-phenylprop-2′-ynyl)-2,6-dimethylaniline ((−)-38; cf. Table 7) in a mixture of 1N H₂SO₄/PrOH at 86° leads to the formation of (−)-(R)-3-(3′-phenylpropa-1′,2′-dienyl)-2,6-dimethylaniline ((−)-91), (+)-(E)- and (−)-(Z)-6-benzylidene-1,5-dimethyltricyclo[3.2.1.0^2′7]oct-3-en-8-one ((+)-(E)- and (−)-(Z)-92, respectively), and (−)-(S)-2,6-dimethyl-4-( 1′-phenylprop-2′-ynyl)aniline((−)-93). Recovered starting material (10%) showed a loss of 18% of its original optical purity. On the other hand, (+)-(E)- and (−)-(Z)-92 showed the same optical purity as (minus;)-38, as expected for intramolecular concerted processes. The CD of (+)-(E)- and (−)-(Z)-92 clearly showed that their tricyclic skeletons possess enantiomorphic structures (cf. Fig. 1). Similar results were obtained from the acid-catalyzed rearrangement of (−)-(S)-N-(3′-chloro-1′phenylprop-2′-ynyl)-2,6-dimethylaniline ((−)-45; cf. Table 7). The recovered starting material exhibited in this case a loss of 48% of its original optical purity, showing that the Cl substituent favors the heterolytic cleavage of the N–C(1′) bond in (−)-45. A still higher degree (78%) of loss of optical activity of the starting aniline was observed in the acid-catalyzed rearrangement of (−)-(S)-2,6-dimethyl-N-[1′-(p-tolyl)prop-2′-ynyl]aniline ((−)-42; cf. Scheme 25). N-[1′-(p-anisyl)prop-2-ynyl]-2,4,6-trimethylaniline(43; cf. Scheme 25) underwent no acid-catalyzed [3,3]-sigmatropic rearrangement at all. The acid-catalyzed rearrangement of N-(1′,1′-dimethylprop-2′-ynyl)aniline (25; cf. Scheme 10) in 1N H₂SO₄/BuOH at 100° led to no product formation due to the sensitivity of the expected product 53 against the reaction conditions. On the other hand, the acid-catalyzed rearrangement of the corresponding 3′-Cl derivative at 130° in aqueous H₂SO₄ in ethylene glycol led to the formation of 1,2,3,4-tetrahydro-2,2-dimethylquinolin-4-on (54; cf. Scheme 10), the hydrolysis product of the expected 4-chloro-1,2-dihydro-2,2-dimethylquinoline (56). Similarly, the acid-catalyzed rearrangement of N-(3′-bromo-1′-methylprop-2′-ynyl)-2,6-diisopropylaniline (37; cf. Scheme 21) yielded, by loss of one i-Pr group, 1,2,3,4-tetrahydro-8-isopropyl-2-methylquinolin-4-one (59).

中文翻译：

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N-炔丙基苯胺的酸催化[3,3]-适亲重排^†

N-（1'，1'-二甲基丙-2'-炔基）-，N-（1'-甲基丙-2'-炔基）-和N-（1'-芳基丙-2'的酸催化重排-Nyn）-2,6-，2,4,6-，2,3,5,6-和2,3,4,5,6-取代的苯胺在1N H ₂ SO ₄水溶液和ROH的混合物中例如EtOH，PrOH，BuOH等，或在CDCl ₃或CCl ₄中，在4至9摩尔当量的存在下。三氟乙酸（TFA）进行了研究（参见方案12 - 25和表6和7）。CDCl中N-（3'-X-1'，1'-二甲基-丙-2'-炔基）-2,6-和2,4,6-三甲基苯胺（X = Cl，Br，I）的重排₃/ TFA在20℃已经发生与τ _1/2 CA的 1至5小时得到相应的6-（1-X-3'-甲基丁基-1,2'-二烯基）-2,6-二甲基-或2,4,6-三甲基环己-2,4-二烯-1 -亚胺离子（参见方案13和脚注26和34）当4位未被取代时，会发生连续的[3,3]-σ重排，从而生成2,6-二甲基-4-（3'-X- 1'，1'-二甲基丙-2'-炔基）苯胺（参见脚注26和34）。N-（3'-氯-1'-苯基丙-2'-炔基）-2,6-二甲基苯胺表现出可比的行为（45。，参见表7）。在1N的H ₂ SO ₄ / ROH水溶液中于85-95°的C（3'）处带有Cl取代基的苯胺的酸催化重排，还会导致形成7-氯三环[3.2.1.0 ^{2， 7} ]辛-3-烯-8-酮作为分子内的结果狄尔斯-阿尔德的初步形成亚胺离子随后亚胺函数的水解（或反应反之亦然;参见方案13,23，和25以及如表7）。当在亚胺离子中间体的C（1'）处没有X取代基时，C（6）处的烯基部分发生[1,2]-σ位移，与[3,3]-σ重排竞争。得到相应的3-烯丙基取代的苯胺（参见方案12、14-18和20以及表6和7）。（-）-（S）-N-（1'-苯丙-2'-炔基）-2,6-二甲基苯胺（（-）- 38 ;参见表7）在1N H ₂ SO的混合物中的重排在86°处的₄ / PrOH导致形成（-）-（R）-3-（3'-苯基丙烷-1'，2'-二烯基）-2,6-二甲基苯胺（（-）- 91），（+）-（E）-和（-）-（Z）-6-亚苄基-1,5-二甲基^三环[3.2.1.0 ^2'7 ] oct-3-en-8-one（（+）- （E）-和（-）-（Z）-92）和（-）-（S）-2,6-二甲基-4-（1'-苯基丙-2'-炔基）苯胺（（- ）-93）。回收的起始原料（10％）损失了其原始光学纯度的18％。另一方面，如分子内协同过程所预期的那样，（+）-（E）-和（-）-（Z）-92的光学纯度与（负）-38相同。（+）-（E）-和（-）-（Z）-92的CD清楚地表明，它们的三环骨架具有对映体结构（参见图1）。从（-）-（S）-的酸催化重排获得了相似的结果N-（3'-氯-1'苯基丙-2'-炔基）-2,6-二甲基苯胺（（-）- 45 ;参见表7）。所述回收的起始在这种情况下表现出其原始光学纯度为48％的损耗材料，显示出氯取代基有利于N-C的异裂（1'）在键（ - ） - 45的静止更高程度（在（-）-（S）-2,6-二甲基-N- [1'-（对甲苯基）prop-2'的酸催化重排中观察到起始苯胺的光学活性损失了78％）-ynyl]苯胺（（-）- 42；参见方案25）。N- [1'-（对茴香基）丙-2-炔基] -2,4,6-三甲基苯胺（43 ;参见方案25）根本没有经过酸催化的[3,3]-σ重排。N-（1'，1'-二甲基丙-2'-炔基）苯胺（25 ;参见方案10）在1N H ₂ SO ₄ / BuOH中在100°下的酸催化重排导致未形成产物预期产物53对反应条件的敏感性。另一方面，相应的3'-Cl衍生物在乙二醇中的H ₂ SO ₄水溶液中在130°下进行酸催化重排导致形成1,2,3,4-四氢-2,2-二甲基喹啉-4-on（54 ;参见方案10），是预期的4-氯-1,2-二氢-2,2-二甲基喹啉（56）的水解产物。类似地，N-（3'-溴-1'-甲基丙基-2'-炔基）-2,6-二异丙基苯胺的酸催化重排（37 ;参见方案21）通过失去一个i-Pr基团而产生，1,2,3,4-四氢-8-异丙基-2-甲基喹啉-4-酮（59）。