Rhodium-Catalyzed Denitrogenative Transannulation of N-Sulfonyl-1,2,3-triazoles with Glycals Giving Pyrroline-Fused N-Glycosides

Abstract

Described here is a selective synthesis of 2,3-dihydropyrrole-fused N-glycosides through rhodium-catalyzed denitrogenative transannulation of N-sulfonyl-1,2,3-triazoles with glycals. A series of pyrroline-fused N-glycosides are afforded in moderate to excellent yields with exclusive regioselectivity and stereoselectivity. Functional application of such a resultant product by oxidative addition and epoxidation is also explored. Notably, the treatment of a pyrroline-fused N-glycoside (3a) with TMSOTf efficiently leads to an interesting unexpected C-nucleoside (9) via a TMSOTf-inducing ring opening/acetyl migration/ring closing reaction sequence.

Radical borylation of vinyl azides with NHC-boranes: divergent synthesis of α-boryl ketones and borylated triazoles

“…14 They can also serve as directing groups in C–H activations and powerful building blocks for various transformations in organic synthesis. 15 Hence, numerous efforts have been made to construct N -substituted 1,2,3-triazoles. 16 It is worth noting that only one method has been reported to date for the synthesis of boryl-substituted triazoles via a [3 + 2]-dipolar cycloaddition of NHC-boryl azides with electron-poor alkynes.…”

Recent Advances in the Synthesis of 5‐MemberedN‐Heterocycles via Rhodium Catalysed Cascade Reactions

“…). [66] Scheme 26. Rhodium(III)-catalyzed oxidative [3 + 2] annulation of 2-acetyl-1-arylhydrazines with maleimides to synthesize pyrrolo [3,4-b]indole-1,3-diones.…”

“…Synthesis of pyrroline-fused N-glycosides via rhodium-catalyzed denitrogenative transannulation of N-sulfonyl-1,2,3-triazoles with glycals. [66] ChemistrySelect precursor for the synthesis of diverse carbo-and heterocycles via rhodium(III)-catalyzed CÀ H activation reaction. Inspired by all these pioneering work Ningning and co-workers, disclosed a new and facile route for the synthesis of 2-arylindoles via rhodium(III)-catalyzed CÀ H activation and a cascade annulation reaction between arylhydrazines and sulfoxonium ylides.…”

“…then consequent electrophilic addition of B to the double bond of glycal 103 , ring opening of the resulting cyclopropane and lastly a nucleophilic attack of the nitrogen atom to intermediate D afforded the desired N ‐glycoside product 104 (Scheme 30). [66] …”

“… Synthesis of pyrroline‐fused N ‐glycosides via rhodium‐catalyzed denitrogenative transannulation of N ‐sulfonyl‐1,2,3‐triazoles with glycals [66] …”