Synthesis of 2-iodoynamides and regioselective [2+2] cycloadditions with ketene

Abstract

The first synthesis of 2-iodoynamides is described as well as the first [2+2] cycloadditions of ketene with iodo alkynes.

Benzannulation via the Reaction of Ynamides and Vinylketenes. Application to the Synthesis of Highly Substituted Indoles

“…26 We recognized that benzannulation with this new class of ynamides could furnish access to 2-iodoanilines whose utility as substrates in a variety of indole-forming annulation processes is well established. We therefore turned our attention to the investigation of tandem strategies based on the application of iodoynamides in our vinylketene-based benzannulation in conjunction with various transition-metal-catalyzed annulation processes (Scheme 10).…”

Terminal ynamides: synthesis, coupling reactions, and additions to common electrophiles

“…24 The amide substrate 43 was first converted to a copper complex with stoichiometric amounts of CuI and KHMDS and then treated with trialkylsilylethynyl halide 39 or 42 (Scheme 10). While this protocol is not catalytic, the reaction occurs at room temperature and several silyl protected ynecarbamates 44 were prepared in superior yields.…”

“…29 As discussed above, the silyl compounds 40 are readily cleaved with TBAF or potassium carbonate to furnish the corresponding terminal ynamides. 24b …”

“…Danheiser’s group recognized the synthetic potential of 2-iodoynamides and prepared 90a–c by deprotonation of terminal ynamides with either n -butyllithium or KHMDS and subsequent addition of iodine or 1,2-diiodoethane as the iodination reagent (Scheme 24). 46 The use of 2-iodoynamides in [2+2] cycloadditions with ketenes was found to provide invaluable access to multifunctional iodocyclobutenones.…”

Synthese hochfunktionalisierter 4‐Aminochinoline

“…[22] Deren Synthese ist generell mçglich durch kupferkatalysierte Anknüpfung von Acetylenderivaten an Sulfonamide mittels Kupfer- [23] oder Eisenkatalyse, [24] durch kupferkatalysierte Kreuzkupplung von 1,1-Dibromalkenen mit Sulfonamiden [25] oder durch Formylierung der Sulfonamide mit anschließender Dibrommethylenierung und nachfolgender Eliminierung zum Inamid. [26] Wirbegannen mit der Schützung der Tosylamine durch reduktive Aminierung mit Benzaldehyd-Derivaten oder mit Furfural [27] oder durch die Reaktion von Benzylamin mit Tosylchlorid;eines der Amide wurde durch Rçntgenstrukturanalyse charakterisiert (siehe 61 in den Hintergrundinformationen).…”