Sequential Catalytic Functionalization of Aryltriazenyl Aldehydes for the Synthesis of Complex Benzenes

Abstract

We demonstrate that aryltriazenes can promote three distinctive types of C–H functionalization reactions, allowing the preparation of complex benzene molecules with diverse substitution patterns. 2-Triazenylbenzaldehydes are shown to be efficient substrates for Rh(I)-catalyzed intermolecular alkyne hydroacylation reactions. The resulting triazene-substituted ketone products can then undergo either a Rh(III)-catalyzed C–H activation, or an electrophilic aromatic substitution reaction, achieving multifunctionalization of the benzene core. Subsequent triazene derivatization provides traceless products.

Synthesis, reactions and application of chalcones: a systematic review

“…80 Moreover, the selective formation of Z sulfenyl chalcones 64 was reported by using Stille cross-coupling with the Z α-sulfenyl-β-chloroenones 62, while the E α-sulfenylβ-chloroenones did not react under the same conditions (Scheme 17). 81,82 3.11. Decarboxylative cross-coupling Jiang et al described the synthesis of different chalcones 67 by the decarboxylation cross-coupling reaction of α-oxo carboxylic acid 65 and cinnamic acid derivatives 66 in an aqueous solution using an iron-facilitated oxidative radical, 83 as shown in Scheme 18.…”

“…Moreover, the selective formation of Z sulfenyl chalcones 64 was reported by using Stille cross-coupling with the Z α-sulfenyl-β-chloroenones 62 , while the E α-sulfenyl-β-chloroenones did not react under the same conditions (Scheme 17). 81,82…”

Development of 3-triazenylaryne and its application to iterative aryne reactions via o-triazenylarylboronic acids

“…8 The reactions with diethylamine ( 4b ), enol silyl ether 4c , and nitrone 4d afforded products 5b – d with virtually complete regioselectivity (entries 2–4) (see ESI† for structure determination). 10 Conversely, the reaction with 2- tert -butylfuran ( 4e ) afforded a regioisomeric mixture of 5e and 5e′ (entry 5, 5e : 5e′ = 60 : 40). To gain insight into the regioselectivity, DFT calculations (B3LYP/6-31+G(d,p)) of 3-triazenylaryne bearing methyl groups, instead of isopropyl groups, were performed.…”

Synthesis of α-Branched Amines by Three- and Four-Component C–H Functionalization Employing a Readily Diversifiable Hydrazone Directing Group

“…1e,g It would be highly desirable to utilize an easily introduced directing group that could later be elaborated into a wide range of different functionalities. 7 We considered the hydrazone as a suitable directing group for this purpose. Hydrazones are easily synthesized in excellent yield by the condensation of a hydrazine and an aldehyde, of which enormous numbers are commercially available.…”

“…It would be highly desirable to utilize an easily introduced directing group that could later be elaborated into a wide range of different functionalities . We considered the hydrazone as a suitable directing group for this purpose.…”