Iridium/Brønsted acid cooperative catalyzed asymmetric allylicsubstitution reactions at the C5 position of indolines have been reported for the first time. The highly efficient protocol allows rapid access to various C5-allylated products in good to high yields (48–97%) and enantioselectivities (82% to >99% ee) with wide functional group tolerance. The transformations allow not only the formation
Hydroxymethylation beyond Carbonylation: Enantioselective Iridium-Catalyzed Reductive Coupling of Formaldehyde with Allylic Acetates via Enantiotopic π-Facial Discrimination
作者:Victoria J. Garza、Michael J. Krische
DOI:10.1021/jacs.6b01078
日期:2016.3.23
2-propanol-mediated reductive coupling of branched allylic acetates 1a-1o with formaldehyde to form primary homoallylic alcohols 2a-2o with excellent control of regio- and enantioselectivity. These processes, which rely on enantiotopic π-facial discrimination of σ-allyliridium intermediates, represent the first examples of enantioselective formaldehyde C-C coupling beyond aldol addition.
SEGPHOS 修饰的手性铱配合物可催化 2-丙醇介导的支链烯丙乙酸酯 1a-1o 与甲醛的还原偶联,形成高烯丙醇 2a-2o,并具有出色的区域选择性和对映选择性控制。这些过程依赖于 σ-烯丙基铱中间体的对映体 π-面辨别,代表了羟醛加成以外的对映选择性甲醛 CC 偶联的第一个例子。
Iridium-Catalyzed Enantioselective Allyl–Allyl Cross-Coupling of Racemic Allylic Alcohols with Allylboronates
作者:Yu Zheng、Bei-Bei Yue、Kun Wei、Yu-Rong Yang
DOI:10.1021/acs.orglett.8b03627
日期:2018.12.21
catalytic system that allows asymmetric allyl–allylboronate cross-coupling with high enantioselectivity is reported. This transformation tolerates a large variety of racemic branched allylicalcohols and allylboronate substrates. The utility of the coupling is demonstrated in a concise catalytic asymmetric synthesis of (−)-preclamol.
In Situ Ring‐Closing Strategy for Direct Synthesis of N‐Heterocyclic Carbene Nickel Complexes and Their Application in Coupling of Allylic Alcohols with Aryl Boronic Acids
作者:Yu‐Bin Wang、Bin‐Yuan Liu、Qingqing Bu、Bin Dai、Ning Liu
DOI:10.1002/adsc.202000186
日期:2020.7.29
A in situ ring‐closing strategy was developed for the synthesis of N‐heterocycliccarbenenickelcomplexes. The process was carried out in air, and did not require solvent purification. The resulting nickelcomplexes were investigated as catalysts for the coupling of allylic alcohols with aryl boronic acids. A wide range of allylic substrates and aryl acids proved to be applicable to this catalytic
A direct route to branched N-allylpyrimidine analogues is herein reported via the highly regio- and enantioselective asymmetricallylation of pyrimidines with racemic allylic carbonates. With [Rh(COD)Cl]2/chiral diphosphine as the catalyst, a range of chiral pyrimidine acyclic nucleosides could be obtained under neutral conditions in good yields (up to 95% yield) with high levels of regio- and enantioselectivities