Enantioselective auto-tandem catalysis represents a challenging yet highlight attractive topic in the field of asymmetric catalysis. In this context, we describe a dual catalytic cycle that merges allylic cyanation and asymmetric hydrocyanation. The one-pot conversion of a broad array of allylic alcohols into their corresponding 1,3-dinitriles proceeds in good yield with high enantioselectivity. The products are densely functionalized and can be easily transformed to chiral diamines, dinitriles, diesters, and piperidines. Mechanistic studies clearly support a novel sequential cyanation/hydrocyanation pathway.
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http://dx.doi.org/10.1002/anie.202000704 | DOI Listing |
Org Lett
August 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
An enantioselective addition reaction of alkynyl esters with imines was developed under asymmetric autotandem catalysis with a chiral Brønsted base. A chiral bis(guanidino)iminophosphorane organosuperbase, which has much higher basicity than that of conventional chiral organic bases, efficiently promoted both the intramolecular cyclization for the construction of a benzofuran ring or a benzothiophene ring and the sequential enantioselective direct Mannich-type reaction of diarylmethane derivatives, affording enantio-enriched diarylalkane derivatives that are otherwise difficult to access.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
June 2023
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China.
σ-Lewis base-catalyzed regio- and enantioselective aza-Morita-Baylis-Hillman (MBH) reaction of α,β,γ,δ-unsaturated systems remains a challenge due to the intrinsic covalent activation mode. Here we demonstrate that a Pd complex can mediate the dehydrogenative reaction of γ,δ-unsaturated compounds to give corresponding electron-poor dienes, which further undergo δ-regioselective umpolung Friedel-Crafts-type addition to imines via auto-tandem Pd -π-Lewis base catalysis. After β-H elimination of in situ formed Pd -complexes, unprecedented and chemically inverse aza-MBH-type adducts are finally furnished with fair to outstanding enantioselectivity, and a diversity of functional groups and both ketimine and aldimine acceptors can be well tolerated.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2022
College of Pharmaceutical Sciences, and Hangzhou Institute of Innovative Medicine, Zhejiang University, Hangzhou, 310058, China.
Angew Chem Int Ed Engl
April 2022
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China.
Developing new asymmetric auto-tandem catalysis processes, especially in a divergent manner, is highly attractive but extremely challenging. Presented herein is a palladium-catalyzed auto-tandem reaction between 2,4-dienyl carbonates and o-TsNH arylimines or trifluoroacetophenones that proceeds through a consecutive N-allylation, vinylogous addition, π-σ-π isomerization, and another N-allylation sequence. Importantly, switchable diastereodivergent synthesis could be achieved by tuning the chiral bisphosphine ligands, which led to the construction of a broad spectrum of fused tetrahydroquinoline architectures with moderate to excellent enantioselectivity.
View Article and Find Full Text PDFChemistry
November 2021
School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia.
A phosphine-catalyzed approach to pyrrolines has been developed that involves two mechanistically unlinked catalytic processes. The first involves the redox isomerization of amino crotonates to provide access to aliphatic tosyl imines, which then engage in a (3+2) annulation with various allenoates. The reaction shows generality, with 24 examples established, along with a low yielding and moderately enantioselective variant.
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