Catalytic Enantioselective Cyclization and C3-Fluorination of Polyenes
摘要:
(Xylyl-phanephos)Pt2+ in combination with XeF2 mediates the consecutive diastereoselective cation-olefin cyclization/fluorination of polyene substrates. Isolated yields were typically in the 60-69% range while enantioselectivities reached as high as 87%. The data are consistent with a stereoretentive fluorination of a P2Pt-alkyl cation intermediate.
[EN] PROCESSES FOR THE PREPARATION OF ORTHO-ALLYLATED HYDROXY ARYL COMPOUNDS<br/>[FR] PROCÉDÉS DE PRÉPARATION DE COMPOSÉS HYDROXY-ARYLE ORTHO-ALLYLÉS
申请人:UNIV MCMASTER
公开号:WO2021237371A1
公开(公告)日:2021-12-02
The present application describes process for preparing an ortho-allylated hydroxy aryl compounds such as compounds of Formula (I) by reacting an allylic alcohol with a hydroxy aryl compound in the presence of aluminum compound selected from alumina and aluminum alkoxides and in a non-protic solvent wherein at least one carbon atom ortho to the hydroxy group in the hydroxy aryl compound is unsubstituted. The present application also includes compounds of Formula (I).
Enantioselective, Lewis Base-Catalyzed Sulfenocyclization of Polyenes
作者:Zhonglin Tao、Kevin A. Robb、Kuo Zhao、Scott E. Denmark
DOI:10.1021/jacs.8b01660
日期:2018.3.14
Homogeranylarenes and ortho-geranylphenols undergo polycyclization in good yield, diastereoselectivity, and enantioselectivity. The stereodetermining step is the generation of an enantiomericallyenrichedthiiraniumion from a terminal alkene and a sulfenylating agent in the presence of a chiral Lewis basic catalyst. The use of hexafluoroisopropyl alcohol as the solvent is crucial to obtain good yields
Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol
2-烯基苯酚和烯酰胺的催化对映选择性卤环化已经通过使用手性酰胺磷酸盐催化剂和卤代路易斯酸实现。密度泛函理论计算表明催化剂的路易斯碱度在反应性和对映选择性中起重要作用。所得手性卤代色满可以在短时间内转化为 α-生育酚、α-生育三烯酚、代达林 A 和英格列酮。此外,具有不饱和侧链的卤化产物可在自由基环化条件下提供多环加合物。
Chiral Lewis Base-Assisted Brønsted Acid (LBBA)-Catalyzed Enantioselective Cyclization of 2-Geranylphenols
Brønsted acids (Chiral LBBAs) have been designed as new organocatalysts for biomimeticenantioselectivecyclization. A salt of a chiral phosphonous acid diester with FSO3H catalyzes the enantioselectivecyclization of 2-geranylphenols to give the desired trans-fused cyclized products with high diastereo- and enantioselectivities (up to 98:2 dr and 93% ee).
NXS, Morpholine, and HFIP: The Ideal Combination for Biomimetic Haliranium-Induced Polyene Cyclizations
作者:Andreas M. Arnold、Alexander Pöthig、Markus Drees、Tanja Gulder
DOI:10.1021/jacs.8b00113
日期:2018.3.28
contrast to Nature that accomplishes polyenecyclizations seemingly with ease, such transformations are difficult to conduct in the lab. In our program dealing with the development of selective halogenations of alkenes, we now asserted that standard X+ reagents are perfectly suited for the biomimetic cation-π cyclization of both electron rich and poor linear polyenes in the presence of the Lewis base