Iridium-Catalyzed Asymmetric Allylic Substitution Reactions

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(3), P. 1855 - 1969

Published: Dec. 24, 2018

In this review, we summarize the origin and advancements of iridium-catalyzed asymmetric allylic substitution reactions during past two decades. Since first report in 1997, Ir-catalyzed have attracted intense attention due to their exceptionally high regio- enantioselectivities. been significantly developed recent years many respects, including ligand development, mechanistic understanding, substrate scope, application synthesis complex functional molecules. an explicit outline ligands, mechanism, scope nucleophiles, applications is presented.

Language: Английский

---

2-Azaallyl Anions, 2-Azaallyl Cations, 2-Azaallyl Radicals, and Azomethine Ylides

Chemical Reviews, Journal Year: 2018, Volume and Issue: 118(20), P. 10393 - 10457

Published: Oct. 10, 2018

This review covers the use of 2-azaallyl anions, cations, and radicals in organic synthesis up through June 2018. Particular attention is paid to both foundational studies recent advances over past decade involving semistabilized nonstabilized anions as key intermediates various carbon–carbon carbon–heteroatom bond-forming processes. Both transition-metal-catalyzed transition-metal-free transformations are covered. Azomethine ylides, which have received significant elsewhere, discussed briefly with primary focus on critical comparisons regard generation use.

Language: Английский

---

A Regio‐ and Stereodivergent Synthesis of Homoallylic Amines by a One‐Pot Cooperative‐Catalysis‐Based Allylic Alkylation/Hofmann Rearrangement Strategy

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(31), P. 10521 - 10527

Published: May 27, 2019

Abstract Herein, we report a modular synthetic route to linear and branched homoallylic amines that operates through sequential one‐pot Lewis base/transition‐metal catalyzed allylic alkylation/Hofmann rearrangement strategy. This protocol is operationally trivial, proceeds from simple easily prepared substrates catalysts, enables all aspects of regio‐ stereoselectivity be controlled conserved experimental protocol. Overall, the high levels enantio‐, regio‐, diastereoselectivity obtained, in concert with ability access orthogonally protected or free amines, render this straightforward effective approach for preparation useful enantioenriched amines. We have also demonstrated utility products context pharmaceutical synthesis.

Language: Английский

---

Recent advances in metal-catalysed asymmetric sigmatropic rearrangements

Chemical Science, Journal Year: 2022, Volume and Issue: 13(42), P. 12290 - 12308

Published: Jan. 1, 2022

Catalytic asymmetric sigmatropic rearrangements induced by chiral metal catalysis have been intensively explored. This review summarizes recent significant advances, mainly involving [3,3], [2,3] and [1,3]-rearrangements.

Language: Английский

---

Enantioselective Iridium‐Catalyzed Allylic Substitution with 2‐Methylpyridines

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(14), P. 4002 - 4005

Published: March 7, 2017

Abstract An enantioselective iridium‐catalyzed allylic substitution with a set of highly unstabilized nucleophiles generated in situ from 2‐methylpyridines is described. Enantioenriched 2‐substituted pyridines, which are frequently encountered natural products and pharmaceuticals, could be easily constructed by this simple method good yields excellent enantioselectivity. The synthetic utility the pyridine demonstrated through synthesis key intermediate reported Na + /H exchanger inhibitor total (−)‐lycopladine A.

Language: Английский

---

Catalytic Asymmetric Synthesis of Trifluoromethylated γ‐Amino Acids through the Umpolung Addition of Trifluoromethyl Imines to Carboxylic Acid Derivatives

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 57(8), P. 2233 - 2237

Published: Dec. 12, 2017

Abstract Novel cinchona alkaloid derived chiral phase‐transfer catalysts enabled the highly chemo‐, regio‐, diastereo‐, and enantioselective umpolung addition of trifluoromethyl imines to α,β‐unsaturated N ‐acyl pyrroles. With a catalyst loading ranging from 0.2 5.0 mol %, this new catalytic asymmetric transformation provides facile high‐yielding access enantiomerically enriched trifluoromethylated γ‐amino acids γ‐lactams.

Language: Английский

---

Double Regioselective Asymmetric C‐Allylation of Isoxazolinones: Iridium‐Catalyzed N‐Allylation Followed by an Aza‐Cope Rearrangement

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 57(5), P. 1404 - 1408

Published: Nov. 17, 2017

Abstract Isoxazolinones are biologically and synthetically interesting densely functionalized heterocycles, which for a long time were not accessible in enantioenriched form by asymmetric catalysis. Next to the deficit of enantioselective methods, functionalization isoxazolinones is often plagued regioselectivity issues due competition various nucleophilic centers within heterocycles. We report first regio‐ C‐allylations isoxazolinones. These occur with high favor linear allylation products, although Ir phosphoramidite catalysts used, commonly results branched isomers. Our studies suggest that this outcome result reaction cascade via an initial N‐allylation provide allyl intermediate, followed spontaneous [3,3]‐rearrangement resulting chirality transfer.

Language: Английский

---

Enantioselective N‐Heterocyclic Carbene Catalysis that Exploits Imine Umpolung

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(12), P. 4007 - 4011

Published: Jan. 21, 2019

The catalytic umpolung of imines remains an underdeveloped approach to reaction discovery. Herein we report enantioselective aza-Stetter that proceeds via imine using N-heterocyclic carbene catalysis. with high levels enantioselectivity (all ≥96:4 er) and good generality (21 examples). Mechanistic studies are reported consistent turnover-limiting addition the NHC imine.

Language: Английский

---

Synergistic catalysis for cascade allylation and 2-aza-cope rearrangement of azomethine ylides

Nature Communications, Journal Year: 2019, Volume and Issue: 10(1)

Published: April 8, 2019

The efficient construction of enantiomerically enriched molecules from simple starting materials via catalytic asymmetric synthesis strategies is a key challenge in synthetic chemistry. Metallated azomethine ylides are commonly-used synthons for the preparation N-heterocycles and α-amino acids. Remarkably, to date, utilization facile access chiral amines has proven elusive. Here, we report that synergistic Cu/Ir-catalytic system combined with careful tuning steric congestion can be used convert aldimine esters variety homoallylic cascade allylation/2-aza-Cope rearrangement. elucidation distinct effects each stereogenic center allylation intermediates on stereochemical outcome chirality transfer rearrangement further guided selection catalysts combination.

Language: Английский

---

Visible-Light-Mediated Umpolung Reactivity of Imines: Ketimine Reductions with Cy₂NMe and Water

Organic Letters, Journal Year: 2018, Volume and Issue: 20(8), P. 2433 - 2436

Published: April 5, 2018

A novel carbanionic reactivity of imines mediated by photoredox catalysis is demonstrated. The umpolung imine exemplified proton abstraction from water as a key step in the reduction benzophenone ketimines to amines (up 98% yield). Deuterium introduced into efficiently using D2O an inexpensive deuterium source (≥95% D ratio). mechanism this unusual transformation probed.

Language: Английский

---