Phosphorous-chiral analogues of 1,1'-Bis(diphenylphosphino)ferrocene: Asymmetric synthesis and application in highly enantioselective rhodium-catalyzed hydrogenation reactions
Phosphorous-chiral analogues of 1,1'-Bis(diphenylphosphino)ferrocene: Asymmetric synthesis and application in highly enantioselective rhodium-catalyzed hydrogenation reactions
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1,1-双(二苯基膦)二茂铁的磷手性类似物：不对称合成及其在高对映选择性铑催化氢化反应中的应用
DOI：
10.1021/jo982481z
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发表时间：
1999
影响因子：
3.6
通讯作者：
M. Lutz
中科院分区：
文献类型：
--
作者：
U. Nettekoven;P. Kamer;P. V. van Leeuwen;Michael Widhalm;A. Spek;M. Lutz
通过不对称合成方法，合成了5个新的含立体异构磷原子的二茂铁配体1a−e（1 = 1，1 '-双（芳基苯基膦基）二茂铁，芳基残基a = 1-萘基，B = 2-萘基，c = 2-茴香基，d = 2-联苯基，e = 9-菲基）.在随后的硼烷保护的磷中心亲核置换反应中，使用（+）-或（-）-麻黄碱作为光学活性助剂，以41 - 65%的总产率得到标题化合物。二茂铁基双膦的绝对构型通过1a、1b和1d的晶体结构分析确认。在铑催化的α-（酰氨基）肉桂酸衍生物的不对称氢化反应中证明了它们作为手性配体的有效性。当使用配体1b和1d时，观察到低反应性或对映体歧视，由二膦1a，1c或1 e制备的原位形成的催化剂实现完全转化和对映体选择性。
Five new ferrocene ligands 1a−e (1 = 1,1‘-bis(aryl-phenylphosphino)ferrocene with aryl residues a = 1-naphthyl, b = 2-naphthyl, c = 2-anisyl, d = 2-biphenylyl, and e = 9-phenanthryl) bearing stereogenic phosphorus atoms have been prepared in enantiomerically pure form via an asymmetric synthesis protocol. The use of (+)- or (−)-ephedrine as the optically active auxiliary during subsequent nucleophilic displacement reactions at borane-protected phosphorus centers gave rise to the title compounds in 41−65% overall yield. The absolute configuration of the ferrocenyldiphosphines was confirmed by crystal structure analysis of 1a, 1b, and 1d. Their efficiency as chiral ligands was demonstrated in rhodium-catalyzed asymmetric hydrogenation reactions of α-(acylamino)cinnamic acid derivatives. While low reactivity or enantiomeric discrimination were observed when employing ligands 1b and 1d, the in situ formed catalysts prepared from diphosphines 1a, 1c, or 1e effected complete conversion and enantioselectivities ...