Asymmetric Inter- and Intramolecular Cyclopropanation Reactions Catalyzed by a Reusable Macroporous-Polymer-Supported Chiral Ruthenium(II)/Phenyloxazoline Complex
Along came poly: A novel macroporous polymer‐supported chiral RuII/pheox catalyst (1, see SEM image) afforded excellent reactivity and enantioselectivity in inter‐ and intramolecular cyclopropanation reactions with a broad range of substrates. The catalyst showed no leaching and could be reused up to 11 times, even after storage.
随之而来的是聚:一种新型的大孔聚合物负载的手性Ru II / pheox催化剂(1,参见SEM图片)在与多种底物的分子间和分子内环丙烷化反应中具有出色的反应性和对映选择性。该催化剂没有浸出,即使在储存后也可以重复使用多达11次。
α-Diazoacetates as Carbene Precursors: Metallosalen-Catalyzed Asymmetric Cyclopropanation
作者:Tsutomu Katsuki、Tatsuya Uchida
DOI:10.1055/s-2006-926448
日期:2006.5
Readily available α-diazo compounds have been shown to be efficient carbene precursors for asymmetric cyclopropanation using ruthenium(NO)-salen and cobalt-salen complexes, as catalysts. The stereoselectivity of the cyclopropanation depends on the metal ion, its valency, the structural and electronic nature of the salen ligand, and the apical ligand of the salen complex used. Both trans- and cis-selective asymmetric intermolecular cyclopropanation can be realized under mild conditions by using a suitable metallosalen complex. Furthermore, a wide range of alkenyl α-diazoacetates and the related alkenyl diazomethyl ketones undergo intramolecular cyclopropanation in a highly enantioselective manner by using various metallosalen complexes, easily prepared in a modular fashion, as catalyst.
Optically active Co(II)–salencomplexes (5 and 7) were found to catalyze highlyenantioselective intramolecular cyclopropanation of 2-alkenyl α-diazoacetates in the presence of N-methylimidazole under high substrate concentration.
Intramolecular Asymmetric Cyclopropanation with (Nitroso)(salen)ruthenium(II) Complexes as Catalysts
作者:Biswajit Saha、Tatsuya Uchida、Tsutomu Katsuki
DOI:10.1055/s-2001-9733
日期:——
Intramolecular cyclopropanation of (E)-2-alkenyl-α-diazoacetates was carried out with good to high enantioselectivity by using (nitroso)(salen)ruthenium(II) complexes as catalysts under photo-irradiation.
Cobalt-based catalysts for the cyclization of alkenes
申请人:Zhang Peter X.
公开号:US20060030718A1
公开(公告)日:2006-02-09
Metal-ligand complexes, including cobalt-ligand complexes, such as a cobalt-porphyrin complex, and their use as catalysts in the cyclization of alkenes.