Magnesium Complexes as Highly Effective Catalysts for Conjugate Cyanation of α,β-Unsaturated Amides and Ketones
作者:Jinlong Zhang、Xihong Liu、Rui Wang
DOI:10.1002/chem.201304835
日期:2014.4.22
Asymmetric cyanation of trimethylsilyl cyanide (TMSCN) with α,β‐unsaturated amides and ketones, respectively, catalyzed by bifunctional mononuclear 1,1′‐bi‐2‐naphthol (BINOL)–Mg and binuclear bis(prophenol)–Mg catalysts was realized. A series of synthetically important 1,4‐cyano products were obtained with good to high enantioselectivities (up to 97 % ee).
A highly enantioselective tandem Michael/ring‐closurereaction of α,β‐unsaturated pyrazoleamides and amidomalonates has been accomplished in the presence of a chiral N,N′‐dioxide–Yb(OTf)3 complex (Tf: trifluoromethanesulfonyl) to give various substituted chiral glutarimides with high yields and diastereo‐ and enantioselectivities. Moreover, this methodology could be used for gram‐scale manipulation
A highly efficient N,N′-dioxide/Gd(III) complex has been developed for the enantioselective conjugate addition of nitroalkanes to α,β-unsaturated pyrazolamides. Under mild reaction conditions, a series of γ-nitropyrazolamides were obtained in good to excellent yields (up to 99%) with excellent enantioselectivities (up to 99% ee). What’s more, the optically active products could be easily transformed
Catalytic Asymmetric Csp3
−H Functionalization under Photoredox Conditions by Radical Translocation and Stereocontrolled Alkene Addition
作者:Chuanyong Wang、Klaus Harms、Eric Meggers
DOI:10.1002/anie.201607305
日期:2016.10.17
photoredox‐mediated C(sp3)−H activation through radical translocation can be combined with asymmetric catalysis. Upon irradiation with visible light, α,β‐unsaturatedN‐acylpyrazoles react with N‐alkoxyphthalimides in the presence of a rhodium‐based chiral Lewis acid catalyst and the photosensitizer fac‐[Ir(ppy)3] to provide a C−C bond‐formation product with high enantioselectivity (up to 97 % ee) and, where applicable
A chiral nickel DBFOX complex as a bifunctional catalyst for visible-light-promoted asymmetric photoredox reactions
作者:Xiang Shen、Yanjun Li、Zhaorui Wen、Shi Cao、Xinyi Hou、Lei Gong
DOI:10.1039/c8sc01219a
日期:——
The enantioselective photoredox reaction of α,β-unsaturated carbonyl compounds and tertiary/secondary α-silylamines was enabled by a readily available single NiII–DBFOX catalyst (DBFOX = 4,6-bis((R)-4-phenyl-4,5-dihydrooxazol-2-yl)dibenzo[b,d]furan) under visible light conditions. The non-precious chiral catalyst is involved in the photochemical process to initiate single electron transfer and at the
α,β-不饱和羰基化合物和叔/仲α-甲硅烷基胺的对映选择性光氧化还原反应是通过易于获得的单一Ni II –DBFOX催化剂实现的(DBFOX = 4,6-bis(( R )-4-苯基-4, 5-二氢恶唑-2-基)二苯并[ b , d ]呋喃)在可见光条件下。非贵重的手性催化剂参与光化学过程以引发单电子转移,同时为随后的自由基转变提供良好组织的手性环境。手性 γ-氨基羧酸衍生物和 γ-内酰胺的形成获得了良好至优异的对映选择性 (80–99% ee)。