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Highly Selective Carbon-Carbon Bond Forming Reactions Catalyzed by Novel Rhodium (II) Complex

新型铑(II)配合物催化的高选择性碳-碳键形成反应

基本信息

批准号：
05453177
负责人：
HASHIMOTO Shunichi
金额：
$ 4.54万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Dirhodium (II) tetra (triphenylacetate), Rh_2 (O_2CCPh_3) _4, featured by the steric bulk of the bridging ligand on the rhodium exhibits an exceptionally high order of selectivity for CH insertion into methylene over methine in catalytic decompositions of alpha-diazo beta-keto esters appended to a cyclic system. Furthermore, the superiority of this novel catalyst to the commonly used catalysts has also been demonstrated by the virtually complete selectivity for aromatic C-H insertion, thus providing an expedient and general entry to variously substituted 1-alkyl-2-indanones.A differentiation of enantiotopic methylene C-H bonds can be effected by devising the novel catalyst, dirhodium (II) tetra [N-phthaloyl- (S) -phenylalaninate], of which the phthalimide group has proven to be crucial for this process. It is worthy of note that the enatiomeric excess up to 80% attained here is the highest known to date for enantioselective intramolecular C-H insertion of alpha-diazo beta-keto esters. While the reaction mechanism is presently unclear, the results obtained so far demonstrate that the matched combination of steric effects of the ester moiety and the electron density of the target C-H bond as well as the ligand effects are responsible for high levels of enantioselectivity. By capitalizing on the same catalyst, a highly selective differentiation of enantiotopic benzene rings has been achieved via formal C-H insertion reaction of 3-alkyl-1-diazo-3,3-diphenyl-2-propanones, leading to the formation of (S) -1-alkyl-1-phenyl-2-indanones with up to 95% ee. Dirhodium (II) tetra [N-phthaloyl- (S) -alaninate] has been demonstrated to be useful for the enantioselective construction of heterocyclic systems by decomposition of alpha-carbomethoxy-alpha-diazoacetamides, giving the carbapenem key intermediates of up to 96% ee.

四（三苯乙酸）dihodium (II) tetratra (triphenylacetate), Rh_2 (O_2CCPh_3) _4在铑上的桥接配体具有立体体积特征，在催化分解环系重氮-酮酯时，对CH插入亚甲基的选择性高于对甲基的选择性。此外，与常用催化剂相比，这种新型催化剂的优越性也被证明是对芳烃碳氢插入几乎完全的选择性，从而为各种取代的1-烷基-2-吲哚酮提供了方便和通用的入口。通过设计新型催化剂dihodium (II) tetratra [n - phthalaloyl - (S) -phenylalaninate]，可以实现对映异构体亚甲基C-H键的分化，其中的邻苯亚胺基团已被证明对这一过程至关重要。值得注意的是，在重氮-酮酯的分子内C-H的对映选择性插入中，高达80%的对映体过剩是迄今为止已知的最高的。虽然反应机制目前尚不清楚，但迄今为止获得的结果表明，酯部分的空间效应和目标C-H键的电子密度以及配体效应的匹配组合是高水平对映体选择性的原因。利用相同的催化剂，通过3-烷基-1-重氮-3,3-二苯基-2-丙烷的正式碳氢插入反应，实现了对映苯环的高度选择性分化，从而形成(S) -1-烷基-1-苯基-2-吲哚酮，其ee含量高达95%。四[n -邻苯二甲酰- (S) -丙氨酸酸二钠]已被证明可以通过分解α -碳甲氧基- α -重氮乙酰胺来对映选择性地构建杂环体系，使碳青霉烯类关键中间体的ee含量高达96%。