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Structure Dependence in Asymmetric Deprotonative Fluorination and Fluorocyclization Reactions of Allylamine Derivatives with Linked Binaphthyl Dicarboxylate Phase-Transfer Catalyst
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2021-09-30 , DOI: 10.1021/jacs.1c06783 Tomoki Niwa 1 , Kousuke Nishibashi 1 , Hitomi Sato 1 , Kiyoshi Ujiie 1 , Kenji Yamashita 1 , Hiromichi Egami 1 , Yoshitaka Hamashima 1
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2021-09-30 , DOI: 10.1021/jacs.1c06783 Tomoki Niwa 1 , Kousuke Nishibashi 1 , Hitomi Sato 1 , Kiyoshi Ujiie 1 , Kenji Yamashita 1 , Hiromichi Egami 1 , Yoshitaka Hamashima 1
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The asymmetric fluorofunctionalization of γ,γ-disubstituted allylamine derivatives (e.g., 3, 7, and 8) was investigated using our dianionic phase-transfer catalyst. Depending on the substituents on the alkene moiety, the reaction afforded chiral allylic fluorides and fluorinated dihydrooxazines in a highly enantioselective manner (up to 99% ee). The absolute stereochemistry of these products was found to be opposite to that in our previously reported fluorocyclization of γ-monosubstituted allylic amides (e.g., 13 and 14). To probe this interesting phenomenon, we investigated the influence of the substitution pattern of the alkene moiety on the reaction by means of NMR experiments and kinetic studies. The rate laws of the deprotonative fluorination and the fluorocyclization of γ,γ-disubstituted substrates were v = k[cat]0.6, while that of the fluorocyclization of γ-monosubstituted substrates was v = k[substrate][cat]0.4. An exponent of less than 1 suggests the involvement of an aggregated state of the catalyst ion pair in the catalytic cycle. Interestingly, a positive nonlinear effect was observed in the reactions of the γ,γ-disubstituted substrates, while a negative nonlinear effect was observed in the case of the γ-monosubstituted substrates. Thus, the reaction pathway depends on the presence or absence of an alkyl substituent at the γ position of the substrates, and on the basis of our mechanistic studies we propose that the active catalytic species for γ,γ-disubstituted substrates is a catalyst ion pair aggregate, whereas that for γ-monosubstituted substrates is the more active monomeric catalyst ion pair species, even though its concentration would be low.
中文翻译：
烯丙胺衍生物与连接的二羧酸联萘相转移催化剂的不对称去质子氟化和氟环化反应中的结构依赖性
使用我们的双阴离子相转移催化剂研究了 γ,γ-二取代烯丙胺衍生物（例如3、7和8 ）的不对称氟官能化。根据烯烃部分上的取代基，该反应以高度对映选择性（高达 99% ee）的方式提供手性烯丙基氟化物和氟化二氢恶嗪。发现这些产物的绝对立体化学与我们之前报道的 γ-单取代烯丙基酰胺（例如13和14）。为了探索这一有趣的现象，我们通过核磁共振实验和动力学研究研究了烯烃部分的取代模式对反应的影响。γ,γ-二取代底物的去质子氟化和氟环化速率规律为v = k [cat] 0.6，而γ-单取代底物的氟环化速率规律为v = k [底物][cat] 0.4. 小于 1 的指数表明催化剂离子对的聚集状态参与了催化循环。有趣的是，在 γ,γ-二取代底物的反应中观察到正非线性效应，而在 γ-单取代底物的情况下观察到负非线性效应。因此，反应途径取决于底物的 γ 位是否存在烷基取代基，基于我们的机理研究，我们提出 γ,γ-二取代底物的活性催化物质是催化剂离子对聚集体，而对于 γ- 单取代底物，是活性更高的单体催化剂离子对物质，即使它的浓度很低。
更新日期：2021-10-13
中文翻译：
烯丙胺衍生物与连接的二羧酸联萘相转移催化剂的不对称去质子氟化和氟环化反应中的结构依赖性
使用我们的双阴离子相转移催化剂研究了 γ,γ-二取代烯丙胺衍生物（例如3、7和8 ）的不对称氟官能化。根据烯烃部分上的取代基，该反应以高度对映选择性（高达 99% ee）的方式提供手性烯丙基氟化物和氟化二氢恶嗪。发现这些产物的绝对立体化学与我们之前报道的 γ-单取代烯丙基酰胺（例如13和14）。为了探索这一有趣的现象，我们通过核磁共振实验和动力学研究研究了烯烃部分的取代模式对反应的影响。γ,γ-二取代底物的去质子氟化和氟环化速率规律为v = k [cat] 0.6，而γ-单取代底物的氟环化速率规律为v = k [底物][cat] 0.4. 小于 1 的指数表明催化剂离子对的聚集状态参与了催化循环。有趣的是，在 γ,γ-二取代底物的反应中观察到正非线性效应，而在 γ-单取代底物的情况下观察到负非线性效应。因此，反应途径取决于底物的 γ 位是否存在烷基取代基，基于我们的机理研究，我们提出 γ,γ-二取代底物的活性催化物质是催化剂离子对聚集体，而对于 γ- 单取代底物，是活性更高的单体催化剂离子对物质，即使它的浓度很低。
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