Rhodium(II)‐Catalysed Skeletal Rearrangement of Ether Tethered N‐Sulfonyl 1,2,3‐Triazoles: a Rapid Approach to 2‐Aminoindanone and Dihydroisoquinoline Derivatives

Abstract

Thes keletal rearrangement of ethert ethered N-sulfonyl-1,2,3-triazolesh as been achieved by rhodium(II) catalysis.T hism ethod offers ar apid entry to 2-aminoindanone andd ihydroisoquinoline architecturesw hich can be furthert ransformed to other valuable building blocks,s uch as vicinal aminoindanols, isoquinolines and isoquinolinones.A pathway involving an azavinyl rhodiumc arbene intermediatewas proposed according to apreliminary mechanistic study.

Synthesis of Cyclopropanes via 1,3-Migration of Acyloxy Groups Triggered by Formation of α-Imino Rhodium Carbenes

“…It is well-known that intramolecular 1, n -migration (or named as 1, n -insertion) is a common reaction mode in carbene chemistry . The popular 1,2-migration of hydride, alkyl, as well as a heteroatom could deliver various substituted alkenes; 1,4- and 1,5-H migration are convenient ways to prepare four- and five-membered cycles, respectively. , Specifically, we reported a 1,4-halo migration of α-imino rhodium carbene producing a dihydroquinoline skeleton . The 1,6-, 1,7-, and even 1,14-migration involving carbene were reported, as well. , …”

“…Transformation of carbene is a long-term topic in our group . Except for the above-mentioned 1,4-halo migration, formal 1,2-migration of acyloxy in a special α-imino rhodium carbene 2 was realized recently in our lab (Scheme C), and the in situ generated azadiene 4 was utilized as an effective 1-aza-[4C] synthon in the synthesis of piperidine derivatives . Benefiting from the stability of the five-membered 1,3-dioxolane intermediate 3 , the 1,2-acyloxy migration had excellent chemoselectivity.…”

Recent Advances in the Synthesis of Heterocycles and Related Substances Based on α‐Imino Rhodium Carbene Complexes Derived from N‐Sulfonyl‐1,2,3‐triazoles

“…The main drawback was selectivity towards the formation of 158 and 159 . Almost at the same time, Huang and co‐workers developed a very similar work to synthesize 2‐aminoindanone and dihydroisoquinoline derivatives …”

Preparation of <em>N</em>-(2-alkoxyvinyl)sulfonamides from <em>N</em>-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines

“…Toward this end, our group initiated development of a new protocol for the synthesis of phthalans 11 that would capitalize on recent advancements in the inter-and intramolecular additions of oxygen-based nucleophiles to Rh(II)-azavinyl carbenoids derived from N-sulfonyl-1,2,3-triazoles. 12,13,14,15,16,17 Our approach features a straightforward two-step protocol for converting terminal alkynes such as 1 into N-sulfonyl-1,2,3-triazoles 2 bearing a pendent alcohol (Figure 1). Subsequently, a Rh(II)-catalyzed denitrogenation / 1,3-OH insertion cascade from 2 provides phthalans 3 having a reactive N-(2-alkoxyvinyl)sulfonamide functional group.…”

“…Since the N-(2-alkoxyvinyl)sulfonamide moiety is a potentially versatile, but relatively underexplored N-and O-containing synthon, 16,17,18,19,20,21,22,23,24,25,26,27 we became interested in studying the reactivity of its fused enol-ether/ene-sulfonamide system under a variety of conditions (Figure 2). After screening various reducing protocols, two methods were identified which led to stable phthalan and/or phenethylamine-containing products (Figure 2, 3 → 4/5).…”