Developing New Cleavage Strategies in a Fluorous Phase Pummerer Cyclative‐Capture Approach for the Synthesis of N‐Heterocycles

Abstract

An efficient, oxidative cleavage of a sulfur linker has been developed for the fluorous phase synthesis of N-heterocycles. The new cleavage strategy facilitates the synthesis of products containing diverse structural features.

Beyond the Pummerer Reaction: Recent Developments in Thionium Ion Chemistry

“…In their studies on fluorous synthesis using a sulfur linker, Procter et al. developed an oxidative tag cleavage–modification protocol that is complementary to the samarium(II) iodide reductive cleavage (see Scheme , Scheme , and Scheme ) 35. Thus, treatment of tagged oxindoles such as 80 with ceric(IV) ammonium nitrate (CAN) resulted in a Pummerer reaction to provide isatins such as 81 in excellent yields.…”

A Fluorous, Pummerer Cyclative‐Capture Strategy for the Synthesis of N‐Heterocycles

“…We subsequently found that the Pummerer, oxidative cleavage of 7 could be carried out in a single step with ceric(iv) ammonium nitrate ( 6 , CAN), giving 20 in quantitative yield (Scheme 2). [20] The oxidative removal of the fluorous tag worked well for a range of tagged oxindoles (Figure 1), giving the expected 1,2-dicarbonyl products in high yield after purification with FSPE. Interestingly, in the reaction of benzazepinone 15 with CAN, the fluorous tag can be removed in the presence of the PMB protecting group to give dihydrobenzazepine-1,2-dione 21 ( Figure 1).…”

Jenseits der Pummerer‐Reaktion: Entwicklungen in der Chemie der Thioniumionen

“…[31] [35] In diesem Fall führte die Behandlung markierter Oxindole wie 80 mit Cer(IV)-ammoniumnitrat (CAN) zu einer Pummerer-Reaktion, bei der Isatine wie 81 -nützliche Intermediate zum Aufbau vielfältiger Strukturenin hervorragenden Ausbeuten gebildet wurden (Schema 26).…”