Catalytic Regio- and Stereoselective Alkene Sulfenoamination for 1,4-Benzothiazine Synthesis

Olefin Difunctionalization for the Synthesis of Tetrahydroisoquinoline, Morpholine, Piperazine, and Azepane

This report outlines a versatile strategy for synthesizing a diverse array of N-heterocycles. By the utilization of common olefins, this simple protocol facilitates their coupling with various bifunctional reagents. Furthermore, it can be integrated with C-H amination techniques to directly produce N-heterocycles in a multicomponent cascade coupling process. The unique bond disconnection logic employed in this process underscores its efficiency in achieving rapid simplification through cascade couplings.

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

Herein, we present the synthesis and utilization of derivatives of 4H-benzo[b][1,4]thiazine-3-carboxylic acid. These benzothiazine compounds were assembled via the coupling of aminothiols and bromopyruvates. Oxidative dimerization of these starting materials was also observed and the corresponding benzothiazine dimers were isolated. Moreover, the coupling of benzothiazines with amino acids was realized. In doing so, an enantioselective synthesis of the nonproteinogenic amino acid 2-amino-3-propylhexanoic acid was accomplished.

Continuous Flow Synthesis of 1,4-Benzothiazines Using Ambivalent Reactivity of (E)-β-Chlorovinyl Ketones: A Point of Reaction Control Enabled by Flow Chemistry

A continuous flow system to 1,4-benzothiazines was developed using the point of reaction control, where the ambivalent (E)-β-chlorovinyl ketones and 2,2'-dithiodianilines were confined in a diffusion controlled flow setting. The successful segregation of reactive chemical species in a flow setting allowed more defined reaction pathways that are not feasible in traditional batch reaction conditions. The point of reaction control in flow systems helps to execute the reactions often plagued with the concurrent generation of multiple chemical species.

Lewis Acid-Catalyzed Halonium Generation for Morpholine Synthesis and Claisen Rearrangement

We disclose here practical strategies toward the synthesis of morpholines and Claisen rearrangement products based on the divergent reactivity of a common halonium intermediate. These reactions employ widely available alkenes in a Lewis acid-catalyzed halo-etherification process that can then transform them into the desired products with exceptional regioselectivity for both activated and unactivated olefins. Our mechanistic probe reveals an interesting regiochemical kinetic resolution process.

Recent developments in the difunctionalization of alkenes with C–N bond formation

Various alkene difunctionalization reactions involving nitridization, diamination, azidation, oxyamination, carboamination, aminohalogenation, and nitration are introduced in this review.

Oxyamination of Unactivated Alkenes with Electron-Rich Amines and Acids via a Catalytic Triiodide Intermediate

An aerobic catalytic oxidation process is described for the olefin oxyamination using acids and primary amines as the sources of O and N. Our mechanistic findings point to the formation of triiodide as a critical catalytic intermediate to account for the tolerance of electron-rich nucleophiles. This dual iodide and copper catalytic system is suitable for a formal [5+1] annulation process to access valuable lactam structures and highlighted by the synthesis of the pharmaceutical Zamifenacin.