Racemic but tropos (chirally flexible) BIPHEP ligands for Rh(I)-complexes: highly enantioselective ene-type cyclization of 1,6-enynes.
Racemic but tropos (chirally flexible) BIPHEP ligands for Rh(I)-complexes: highly enantioselective ene-type cyclization of 1,6-enynes.
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DOI：
10.1021/ol048604l
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发表时间：
2004-09
期刊：
影响因子：
5.2
通讯作者：
K. Mikami;Shohei Kataoka;Yukinori Yusa;K. Aikawa
中科院分区：
文献类型：
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作者：
K. Mikami;Shohei Kataoka;Yukinori Yusa;K. Aikawa
[反应：室温下BIPHEP-Rh络合物的tropos（手性柔性）或atropos（手性刚性）性质关键取决于络合的胺。脂肪族DPEN络合物是atropos，而芳香族DABN络合物是tropos。因此，BIPHEP-Rh手性可以在室温下由DABN控制。不含胺的BIPHEP-Rh络合物是tropos。在5 ℃下，即使是无胺的BIPHEP-Rh络合物也是atropos，因此可以用作对映体纯催化剂，在1，6-烯炔的烯型环化中提供高的对映体选择性。
[reaction: see text] The tropos (chirally flexible) or atropos (chirally rigid) nature of BIPHEP-Rh complexes at room temperature critically depends on the amines complexed. The aliphatic DPEN complex is atropos, whereas the aromatic DABN complex is tropos. BIPHEP-Rh chirality can thus be controlled by DABN at room temperature. The amine-free BIPHEP-Rh complex is tropos. At 5 degrees C, even amine-free BIPHEP-Rh complexes are atropos and hence can be used as enantiopure catalysts to give high enantioselectivity in ene-type cyclization of 1,6-enynes.