Access to Saturated Thiocyano-Containing Azaheterocycles via Selenide-Catalyzed Regio- and Stereoselective Thiocyanoaminocyclization of Alkenes

Abstract

An efficient route for the synthesis of saturated thiocyano-containing azaheterocycles by selenide-catalyzed regio- and stereoselective thiocyanoaminocyclization of alkenes is disclosed. The desired products were obtained in moderate to high yields under mild conditions. The generality of this method was elucidated by its efficient application in thiocyano oxycyclization of alkenes.

Phosphoric Acid Catalyzed Electrophilic Thiocyanation of Indoles: Access to SCN‐Containing Aryl‐Indole Compounds

“…We are pleased to find that the use of compound 5 a as an additive can improve the yield to 90% (entry 6). We speculated that 5 a which acted as a Lewis base, might react with reagent 2 a to form more active ion intermediate in the presence of 4 a [3f] . Finally, a series of different solvents were carefully screened, but no better yield was observed (entries 7–8).…”

“…In 2019, we designed and synthesized an electrophilic N‐thiocyanodibenzenesulfonimide (NTSI) reagent, which has been applied for thiocyano oxyfunctionalizations of alkenes and thiocyano semipinacol rearrangement of allylic alcohols [3d–e] . Zhao and coworkers reported selenide catalyzed thiocyanoamination and thiocyanoetherification of 1,2‐disubstituted alkenes [3f] . Besset group also developed some new electrophilic thiocyanating reagents for the preparation of SCN‐containing compounds [3j] .…”

Design and Use of Electrophilic Thiocyanating and Selenocyanating Reagents: An Interesting Trend for the Construction of SCN‐ and SeCN‐Containing Compounds

“…One year later, Zhao and co‐workers developed a selenide‐catalyzed thiocyanoamino cyclization of the alkene derivatives 42 by using the electrophilic N ‐thiocyanatosaccharin VI as the SCN source (Scheme 17). [24] In the presence of a catalytic amount of diphenyl selenide and a Lewis acid (BF 3 ⋅ Et 2 O), an access to SCN‐containing azaheterocycles was achieved with a good regioselectivity and an excellent diastereoselectivity (>19:1). When the reaction was carried out with alkenes bearing an aromatic moiety as the R 1 substituent ( 42 a – 42 d ), the corresponding products selectively resulted from a 6‐ endo ‐cyclization ( 43 a – 43 d ).…”

Synthetic and Mechanistic Studies on 2,3-Dihydrobenzo[b][1,4]-oxaselenines Formation from Selenocyanates

“…1 Organoselenium compounds have experienced an incessantly growing interest for their chemical behavior, reactivity, and their scope for carrying out unique chemical reactions. [5][6][7][8][9] Certainly, these selenium-containing compounds are widely distributed bearing a large structural diversity and, for that reasons, they are gaining relevance either from the pharmaceutical point of view or from their biological properties. 10,11 In fact, many selenium-containing molecules exhibit a wide range of pharmacological activities such as antiviral agents, antiinflammatory agents, antitumor agents, etc.…”