Highly Enantioselective Fluorination of Unprotected 3-Substituted Oxindoles: One-Step Synthesis of BMS 204352 (MaxiPost)
摘要:
The catalytic enantioselective fluorination of N-H-free 3-substituted oxindoles was accomplished by a Sc(III)/N,N'-dioxide complex. Under mild reaction conditions, a series of 3-aryl- and 3-alkyl-3-fluoro-2-oxindoles were obtained in excellent yields (up to 98%) and enantioselectivities (up to 99% ee) by using N-fluorobisbenzenesulfonimide (NFSI) as the fluorination agent. MaxiPost was synthesized efficiently in 81% yield with 96% ee.
Sc takes action: The highly enantioselectivehydroxyaminationreaction of N‐unprotected 2‐oxindoles with nitrosoarenes has been realized using the Sc(OTf)3/L1 complex. The catalyst system exhibited remarkably broad substrate scope and high efficiency. This transformation is the first example of a chiral ScIII/enolate activating a nitrosoarene, and can be conducted on a gram scale without loss in the
Sc发挥作用:使用Sc(OTf)3 / L1络合物实现了N-未保护的2-氧吲哚与亚硝基芳烃的高度对映选择性羟基胺化反应。该催化剂体系表现出显着的底物范围和高效率。该转化是手性Sc III /烯酸酯活化亚硝基芳烃的第一个实例,并且可以以克级进行,而不会损失ee 值。
Highly Enantioselective Synthesis of 3-Amino-2-oxindole Derivatives: Catalytic Asymmetric α-Amination of 3-Substituted 2-Oxindoles with a Chiral Scandium Complex
A highly enantioselective α‐amination of 3‐substitutedoxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)3/N,N′‐dioxide complex (Tf: triflate) has been developed and affords the corresponding 3‐amino‐2‐oxindole derivatives in high yields (up to 98 %) with excellent enantioselectivities (up to 99 % ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent
Catalytic asymmetric α‐arylation of N‐unprotected 3‐substituted oxindoles with diaryliodoniumsalts has been realized by a chiral Lewis acid promoted electrophilic addition and aryl‐rearrangement process. Single C3‐arylated products containing a quaternary carbon center were generated in high enantioselectivity and reactivity.
An efficient enantioselective alkylation of N‐unprotected 3‐substitutedoxindoles was realized by using a chiral N,N′‐dioxide/scandium(III) complex as the catalyst. A wide range of 3,3‐dialkyl substitutedoxindoles with quaternary stereocenters were obtained in high yields and ee values (up to 98% yield and 99% ee).
3‐substituted oxindoles to dienylketones has been developed. This procedure tolerates a relatively wide range of 3‐substituted oxindoles under mild conditions, facilitating the preparation of various chiral oxindoles with quaternary stereocenters. In addition, the reliable catalyst was found to be effective in the asymmetric 1,6‐addition of both δ‐unsubstituted and δ‐methyl‐substituted dienylketones, achieving