Application Of Nitrosamines Or Ammonium Thiocyanate As Bifunctional Reagents In Organic Synthesis

Organic chemistry has long been a fundamentally important subject,and scientific innovation increasingly depends on chemical transformations that provide sustainable,atom-economic access to chemical complexity.The formation of multiple bonds mandating just a single reagent can rapidly increase the construction of complex target molecules and avoid using protective groups.Thus,it is one of the principal aspirations researchers have been pursuing.So far,remarkable achievements have been made in synthetic chemistry using commercially available chemical starting materials or presynthesized precursors as bifunctional reagents.Nitrogen and sulfur are the main elements of organisms,so the construction of C-N C-S bonds has always been a hot field of chemical research.However,reports using nitrogen-or sulfur-containing bifunctional precursors for synthesis are limited.Based on our group's continuous focus on visible light-catalyzed radical chemistry,this research mainly involves the use and pre-preparation of bifunctional nitrogen-and sulfur-containing substrates to synthesize a series of highly functionalized compounds.This paper mainly includes the following five aspects:1.Based on the background of C-N bond construction,the strategies for generating nitrogen-centered radicals that rely on energy transfer and direct excitation are briefly described.According to its development status,the research objectives are formulated.2.Vicinal diamine motif is widely present in natural products and pharmaceutical molecules.The simultaneous introduction of two amino groups across alkene feedstock is an appealing yet challenging approach for synthesizing 1,2-diamines.We successfully developed N-nitrososulfoximides as simple,useful bifunctional reagents,affording the installation of both N-centered sulfonamidyl and NO radicals into alkene and 1,3-diene feedstocks.Both(E)-and(Z)-?-amino-ketoximes are selectively accessible by switching photocatalysts' different triplet exciting energies.Experimental and density functional theory(DFT)computational studies suggest that the reaction proceeds through a sensitized triplet energy transfer pathway.3.Azaspirocyclic compounds frequently offer a versatile motif in drug discovery mainly due to their inherent structural diversity and rigidity.Dearomatic bifunctionalization reaction through C-N bond construction represents an effective method to synthesize azaspiro skeletons.Using nitrosamide as the precursor of amidyl and NO radical,we successful realized the regioselective diaromatic diamination of unactivated arenes by visible-light catalyst non-redox strategy,and synthesized a series of spirocyclizative 1,4-diamine and 1,2-diamine products.This strategy achieves complete atom economy while avoiding the use of sensitizers.4.In addition to pre-prepared substrates,we also expected to use commercially available starting materials as bifunctional reagents.Ammonium thiocyanate is a common inorganic salt containing both ammonium and thiocyanate ions and is usually used as a single thiocyanate reagent.Here,we achieved aminothiocyanation of ?-ketoesters by a visible-light-catalyzed aerobic oxidation strategy using ammonium thiocyanate as both thiocyanate and amino reagents.In the reaction,dioxygen in the air is used as an external oxidant.The net reaction is very clean,and water is the only byproduct.These characters meet the requirements of sustainable development.5.The synthetic advantages and disadvantages of our developed bifunctional reagents are summarized in this section.Moreover,the prospects of biofunctionalization using energy transfer and direct sensitization strategies are forecasted.