Ambient Temperature Metal-Free Thiomethylation of Chloroheteroarenes and Chloropurines

Herein, we report an in-situ mild and metal-free protocol for thiomethylation of heteroarenes in high yields. The thiomethylation of various chloropurines, nucleosides, and chloroheteroarenes has been accomplished offering easy access to agrochemicals and synthetic molecules useful for drug discovery.

Green chemistry meets medicinal chemistry: a perspective on modern metal-free late-stage functionalization reactions

The progress of drug discovery and development is paced by milestones reached in organic synthesis. In the last decade, the advent of late-stage functionalization (LSF) reactions has represented a valuable breakthrough. Recent literature has defined these reactions as the chemoselective modification of complex molecules by means of C-H functionalization or the manipulation of endogenous functional groups. Traditionally, these diversifications have been accomplished by organometallic means. However, the presence of metals carries disadvantages related to their cost, environmental hazard and health risks. Fundamentally, green chemistry directives can help minimize such hazards through the development of metal-free LSF methodologies. In this review, we expand the current discussion on metal-free LSF reactions by providing an overview of C(sp2)-H, and C(sp3)-H functionalizations, as well as the utilization of heteroatom-containing functional groups as chemical handles. Selected topics such as metal-free cross-dehydrogenative coupling (CDC) reactions, organocatalysis, electrochemistry and photochemistry are also discussed. By writing the first review on metal-free LSF methodologies, we aim to highlight current advances in the field with examples that reveal specific challenges and solutions, as well as future research opportunities.

Lewis Basic Salt-Promoted Organosilane Coupling Reactions with Aromatic Electrophiles

Lewis basic salts promote benzyltrimethylsilane coupling with (hetero)aryl nitriles, sulfones, and chlorides as a new route to 1,1-diarylalkanes. This method combines the substrate modularity and selectivity characteristic of cross-coupling with the practicality of a base-promoted protocol. In addition, a Lewis base strategy enables a complementary scope to existing methods, employs stable and easily prepared organosilanes, and achieves selective arylation in the presence of acidic functional groups. The utility of this method is demonstrated by the synthesis of pharmaceutical analogues and its use in multicomponent reactions.