通过使用手性Ni II / N,N'-二氧化物络合物作为催化剂,已实现了对β,γ-不饱和α-酮酸酯的烯丙基硼酸的高度对映体选择性形式共轭烯丙基加成。该转化过程通过烯丙基硼化/ oxy-Cope重排序列进行,提供了简便且快速的途径,以中等至良好的收率(65-92%)和出色的ee值(90-99%ee)转化为γ-烯丙基-α-酮酸酯)。1,2-烯丙基化产物的分离提供了对随后oxy-Cope重排反应机理的认识:底物诱导的手性转移和手性Lewis酸加速过程。在实验研究和DFT计算的基础上,提出了一种罕见的船状过渡态模型,作为氧-科普重排过程中高手性转移的起源。
A bioinspired radical oxidative α-oxyamination of pyruvate with an oxoammonium salt through multiple-site concerted proton–electron transfer process has been developed, which was facilitated by anchoring the mercapoto chains as a “hopping” site at the γ-position of α-keto esters.
diastereo-, and enantioselective Diels–Alderreaction of β,γ-unsaturated α-ketoesters with (E)-1-phenyl dienes has been accomplished by using a stable and easily available chiral N,N′-dioxide/zinc(II) complex as catalyst. Only one isomer of the corresponding cyclohexenes with three chiral centers was obtained in good to excellent yields with excellent ee values under mild reaction conditions. The configurations
Organocatalytic stereospecific vicinal dicholorination of a wide variety of functionalized olefins such as ketoesters, esters, ketones, carvone, cholesterol and ethyl sorbate (27 examples) was achieved using inexpensive sulfuryl chloride as well as a simple phosphine catalyst under mild reaction conditions. The products were obtained with good to excellent yields and diastereoselectivities (up to 96%
A new double annulation cascade involving a [2 + 2] cycloaddition–retroelectrocyclization (CA–RE) process was first reported, leading to the generation of unprecedented dibenzoannulated naphtho[2,1-b]oxecines with good to excellent yields and high stereoselectivity through catalytic scission/recombination of C–C double bonds under the mild conditions. An Y(OTf)3-catalyzed three-component reaction of
首次报道了涉及[2 + 2]环加成-逆电环化(CA-RE)过程的新双环带反应级联反应,从而产生了史无前例的二苯并环烷萘[ 2,1- b ]辛硫辛酮,具有良好的收率和优异的立体选择性,并通过在温和条件下催化双键断裂– C–C双键的重组。Y(OTf)3催化α-炔基萘-2-醇与β,γ-不饱和α-酮酸酯的三组分反应,可以使萘环直接扩环,并实现α-的碳-碳双键裂解/重排酮酸酯以提供大环结构。
Asymmetric Synthesis of Fused Bicyclic<i>N,O</i>- and<i>O,O</i>-Acetals via Cascade Reaction by Gold(I)/<i>N,N</i>′-Dioxide-Nickel(II) Bimetallic Relay Catalysis
hetero‐Diels‐Alder cascadereaction of β,γ‐unsaturated α‐ketoesters with alkyl amides or alcohols were accomplished. The process was based on the utilization bimetallic catalyst system with achiral gold(I) catalyst and chiral N,N′‐dioxide/Ni(II) catalyst, delivering a variety of fused bicyclic N,O‐acetals or O,O‐acetals in up to 99% yield and 99% ee with >19:1 dr under mild reaction conditions. Based