Enantioselective Synthesis of 1-Aryltetrahydroisoquinolines

Facile Synthesis and Utilization of Bis(o-phosphinophenyl)zinc as Isolable PZnP-pincer Ligands Enabled by Boron-Zinc Double Transmetallation

Bis(o-phosphinophenyl)zinc derivatives were successfully synthesized by the reaction of o-phosphinophenylboronates with dimethylzinc via boron-zinc double transmetallation. The transmetallation was significantly accelerated by the presence of the ortho PR2 substituent to...

Enantioselective Synthesis of 1-Aryl Tetrahydroisoquinolines by the Rhodium-Catalyzed Reaction of 3,4-Dihydroisoquinolinium Tetraarylborates

The 1-aryl tetrahydroisoquinolines (1-aryl THIQs) are omnipresent in biologically active molecules. Here we report on the direct asymmetric synthesis of these valuable compounds via the reaction of 3,4-dihydroisoquinolinium tetraarylborates. The dual roles of anionic tetraarylborates, which function as both prenucleophiles and stabilizers of 3,4-dihydroisoquinolinium cations, enable this rhodium(I)-catalyzed protocol to convergently provide enantioenriched 1-aryl THIQs in good yields (≤95%) with ≤97% ee, as demonstrated by the formal synthesis of (-)-solifenacin and the facile synthesis of (-)-Cryptostyline I.

Asymmetric Synthesis of C1-Chiral THIQs with Imines in Isoquinoline Rings

Tetrahydroisoquinoline (THIQ) scaffolds are important structural units that widely exist in a variety of natural alkaloids and synthetic analogues. Asymmetric synthesis of C1-chiral THIQ is of particular importance due to its significant pharmaceutical, agrochemical, and other biological activities, and the usually distinct bioactivities exhibited by the two enantiomers. In this review, we highlight the significant advances achieved in this field, present recent asymmetric synthesis with imines in isoquinoline rings ordered according to the sequence of various substrate types. New strategies could be inspired and more types of substrates need further development.

1 Introduction

2 Catalytic Asymmetric Reaction of Dihydroisoquinolines

2.1 Asymmetric Reactions of 3,4-Dihydroisoquinolines

2.2 Asymmetric Reactions of Dihydroisoquinolinium Salts

2.3 Asymmetric Reactions of C,N-Cyclic N′-Acyl Azomethine Imines

2.3.1 NED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines

2.3.2 IED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines

2.3.3 [3+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines

2.3.4 [4+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines

2.3.5 Asymmetric Addition Reactions to C,N-Cyclic N′-Acyl Azomethine Imines

2.4 Asymmetric Reactions of C,N-Cyclic Nitrones

3 Catalytic Asymmetric Mannich Reactions of Isoquinolines

4 Conclusions and Perspectives

Approach to Chiral 1-Substituted Isoquinolone and 3-Substituted Isoindolin-1-one by Addition-Cyclization Process

An approach to access 1-substituted isoquinolones has been developed through the addition-cyclization of imines with Grignard reagents in the presence of 2,2'-dipyridyl. A number of substituted aromatic magnesium reagents were amenable to this process, and the desired products were obtained with excellent yields and outstanding diastereoselectivities ( dr > 99:1). The utility of this convenient approach is demonstrated by the formal synthesis of ( S)-cryptostyline II. Moreover, N-methylmorpholine (NMM) was found to be an effective additive for the formation of 3-substituted isoindolin-1-ones using one-pot addition-cyclization-deprotection of imine with Grignard reagents.

Asymmetric Synthesis of Isoquinoline Alkaloids: 2004-2015

In the past decade, the asymmetric synthesis of chiral nonracemic isoquinoline alkaloids, a family of natural products showing a wide range of structural diversity and biological and pharmaceutical activity, has been based either on continuation or improvement of known traditional methods or on new, recently developed, strategies. Both diastereoselective and enantioselective catalytic methods have been applied. This review describes the stereochemically modified traditional syntheses (the Pictet-Spengler, the Bischler-Napieralski, and the Pomeranz-Fritsch-Bobbitt) along with strategies based on closing of the nitrogen-containing ring B of the isoquinoline core by the formation of bonds between C₁-N₂, N₂-C₃, C₁-N₂/N₂-C₃, and C₁-N₂/C₄-C_4a atoms. Methods involving introduction of substituents at the C1 carbon of isoquinoline core along with syntheses applying various biocatalytic techniques have also been reviewed.

Zinc-Catalyzed Alkyne Oxidation/C-H Functionalization: Highly Site-Selective Synthesis of Versatile Isoquinolones and β-Carbolines

An efficient zinc(II)-catalyzed alkyne oxidation/C-H functionalization sequence was developed, thus leading to highly site-selective synthesis of a variety of isoquinolones and β-carbolines. Importantly, in contrast to the well-established gold-catalyzed intermolecular alkyne oxidation, over-oxidation can be completely suppressed in this system and the reaction most likely proceeds by a Friedel-Crafts-type pathway. Mechanistic studies and theoretical calculations are described.

Base-promoted coupling of carbon dioxide, amines, and N-tosylhydrazones: a novel and versatile approach to carbamates

A base-promoted three-component coupling of carbon dioxide, amines, and N-tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance, wide substrate scope, and a facile work-up procedure.

Novel strategies for catalytic asymmetric synthesis of C1-chiral 1,2,3,4-tetrahydroisoquinolines and 3,4-dihydrotetrahydroisoquinolines

This review summarizes recent progress in catalytic asymmetric construction of 1,2,3,4-tetrahydroisoquinolines and 3,4-dihydroisoquinolines, among the most important “privileged scaffolds”.

Amine-catalyzed enantioselective 1,3-dipolar cycloadditions of aldehydes to C,N-cyclic azomethine imines

Amine-catalyzed enantioselective 1,3-dipolar cycloadditions of aldehydes to C,N-cyclic azomethine imines were developed. The reactions between diversely substituted C,N-cyclic azomethine imines and aldehydes proceeded smoothly in the presence of chiral prolinol silyl ether catalyst and gave the C-1-substituted tetrahydroisoquinolines in a highly stereoselective manner. These tetrahydroisoquinolines could be efficiently transformed to several other useful polycyclic frameworks.

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

This review which is the second in this series summarises the most common synthetic routes as applied to the preparation of many modern pharmaceutical compounds categorised as containing a six-membered heterocyclic ring. The reported examples are based on the top retailing drug molecules combining synthetic information from both scientific journals and the wider patent literature. It is hoped that this compilation, in combination with the previously published review on five-membered rings, will form a comprehensive foundation and reference source for individuals interested in medicinal, synthetic and preparative chemistry.

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

This review which is the second in this series summarises the most common synthetic routes as applied to the preparation of many modern pharmaceutical compounds categorised as containing a six-membered heterocyclic ring. The reported examples are based on the top retailing drug molecules combining synthetic information from both scientific journals and the wider patent literature. It is hoped that this compilation, in combination with the previously published review on five-membered rings, will form a comprehensive foundation and reference source for individuals interested in medicinal, synthetic and preparative chemistry.

Direct functionalization of (un)protected tetrahydroisoquinoline and isochroman under iron and copper catalysis: two metals, two mechanisms

A highly facile, straightforward synthesis of 1-(3-indolyl)-tetrahydroisoquinolines was developed using either simple copper or iron catalysts. N-protected and unprotected tetrahydroisoquinolines (THIQ) could be used as starting materials. Extension of the substrate scope of the pronucleophile from indoles to pyrroles and electron-rich arenes was realized. Additionally, methoxyphenylation is not limited to THIQ but can be carried out on isochroman as well, again employing iron and copper catalysis.