Catalyst-Controlled Switch in Diastereoselectivities: Enantioselective Construction of Functionalized 3,4-Dihydro-2<i>H</i>-thiopyrano[2,3-<i>b</i>]quinolines with Three Contiguous Stereocenters

Ping, Xin-Ni; Wei, Pei-Shun; Zhu, Xiaoqian; Xie, Jian‐Hua

doi:10.1021/acs.joc.6b02688

Cited by 24 publications

(28 citation statements)

References 31 publications

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“…Despite their stability to moisture and oxygen and being environmentally friendly, cinchona alkaloids possess various functionalities that are available for chemical modifications . The C9 modification of cinchona alkaloids have been largely reported as ester or ether derivatives and the C9‐amino derivatives such as thiourea or urea derivatives ,,,. In addition, the N1 derivatives of cinchona alkaloids have been applicable in phase transfer catalysis .…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Crosslinked Chiral Polysiloxanes of Cinchona Alkaloid Derivatives and their Applications in Asymmetric Catalysis

Kumpuga

Itsuno

2019

Asian J Org Chem

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Crosslinked chiral polysiloxanes containing cinchona alkaloid derivatives were synthesized from poly (methylhydrosiloxane) by hydrosilylation reaction. The C3vinyl group of cinchona alkaloid derivatives were easily hydrosilylated with SiÀ H functional groups of poly(methylhydrosiloxane) by using Pt catalyst. The reaction between cinchona alkaloid dimers and poly(methylhydrosiloxane) and afforded the crosslinked chiral polysiloxanes. Partial hydrolysis of SiÀ H bonds with Pt catalyst during reaction resulted in a formation of extra crosslinkages of chiral polysiloxanes. Mixed solvent (toluene and DMF) system was employed for a successful immobilization of C6'À OH free cinchona alkaloid derivatives into poly(methylhydrosiloxane). Both cinchona alkaloid C9-ester and C9-urethane derivatives were incorporated into poly(methylhydrosiloxane) through SiÀ C bond. The resulted crosslinked chiral polysiloxanes were insoluble in common organic solvents. Their catalytic performance was evaluated in asymmetric Michael addition reactions. The chiral polysiloxanes of cinchona alkaloid having C6'À OH showed higher enantioselectivities (up to 99% ee) with sufficient catalytic activities in the Michael addition reactions. The chiral polysiloxanes were easily recovered by filtration or centrifugation method and could be reused for several times without losing their catalytic performance.[a] B. T. Kumpuga, Prof. S. Itsuno

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Section: Methodsmentioning

confidence: 99%

Synthesis of Crosslinked Chiral Polysiloxanes of Cinchona Alkaloid Derivatives and their Applications in Asymmetric Catalysis

Kumpuga

Itsuno

2019

Asian J Org Chem

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“…In 2017, Xie et al reported a Michael addition–Henry cascade strategy for the synthesis of functionalized 3,4‐dihydro‐2 H ‐thiopyrano[2,3‐ b ]quinolines 22 catalysed by the cinchona based bifunctional thiourea catalyst C‐1 . [ 22b ] The Michael adduct 23 formed after the intermolecular conjugate addition between aromatic thiol 24 and nitrostyrenes 11 undergoes an intramolecular Henry ring closure through less hindered Re‐face of the carbonyl group to furnish the product 22 in excellent yields (90–98 %) with very high stereoselectivities (Scheme 5A).…”

Section: Thiourea‐tertiary Amine Catalyst Based Relay Cascade Catamentioning

confidence: 99%

Thiourea–Tertiary Amine Promoted Cascade Catalysis: A Tool for Complexity Generation

2020

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The bifunctional organocatalyst promoted, relaycascade catalysis (use of a single catalyst capable of promoting each catalytic cycle in the designed cascade process) has been the hot area of research in recent times, as it enables the green synthesis of complex molecular architectures in an atom, cost, and step-economic fashion. In this context we summarized the recent developments in the area of the thiourea-tert-amine based cascade catalysis in the current review article. The discussion was divided into three subsections. double-, triple-, and quadruple cascades depending on the number of individual [a] Dr.

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“…Among the squaramide-based organocatalysts, the alkaloid-squaramide catalyst 135 has provided the best results in the preparation of thiochromans 168 ( Scheme 54 a) [ 183 ]. Following the same idea and type of catalyst, the sulfa-Michael addition to a nitroalkene can be followed by a Henry reaction, allowing the preparation of thiopyran motifs in an enantioselective manner as described in the synthesis of dihydrothiopyrano[2,3- b ]quinolines 169 ( Scheme 54 b) [ 184 ]. For the latter case, the use of another alkaloid-based organocatalysts has allowed to reverse the diastereoselectivity of the transformation.…”

Section: Sulfur Nucleophilesmentioning

confidence: 99%

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

et al. 2017

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The asymmetric conjugate addition of carbon and heteroatom nucleophiles to nitroalkenes is a very interesting tool for the construction of highly functionalized synthetic building blocks. Thanks to the rapid development of asymmetric organocatalysis, significant progress has been made during the last years in achieving efficiently this process, concerning chiral organocatalysts, substrates and reaction conditions. This review surveys the advances in asymmetric organocatalytic conjugate addition reactions to α,β-unsaturated nitroalkenes developed between 2013 and early 2017.

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Catalyst-Controlled Switch in Diastereoselectivities: Enantioselective Construction of Functionalized 3,4-Dihydro-2H-thiopyrano[2,3-b]quinolines with Three Contiguous Stereocenters

Cited by 24 publications

References 31 publications

Synthesis of Crosslinked Chiral Polysiloxanes of Cinchona Alkaloid Derivatives and their Applications in Asymmetric Catalysis

Synthesis of Crosslinked Chiral Polysiloxanes of Cinchona Alkaloid Derivatives and their Applications in Asymmetric Catalysis

Thiourea–Tertiary Amine Promoted Cascade Catalysis: A Tool for Complexity Generation

Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

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