Substituted 1H‐1,2,3‐Triazol‐4‐yl‐1H‐pyrrolo[2,3‐b]pyridines by De Novo One‐Pot Ring‐Forming Coupling/Cyclization/Desilylation Cu Alkyne/Azide Cycloaddition (AAC) Sequence

Abstract

Substituted 1H-1,2,3-triazol-4-yl-pyrrolo[2,3-b]pyridines are efficiently prepared by a one-pot coupling/cyclization/desilylation Cu alkyne/azide cycloaddition (CuAAC) sequence in the sense of a consecutive three-component fashion. The key feature of this new de novo formation of azole and triazole anellation is the sequentially Pd/Cu-catalyzed process employing tri(iso-propyl)silyl (TIPS) butadiyne as a four-carbon building block. In addition, the sequence can be expanded in a four-component fashion also employing the in situ formation of the required azides.

Alkynylation‐Desilylation‐Alkynylation‐Cycloisomerization (ADAC) Three‐Component Synthesis of 2,2′‐Biindolyls – Concise Synthesis of Tjipanazole I

“…The unsymmetrical nature of TIPS‐protected butadiyne ( 2 ) allows the formation of unsymmetrically substituted diynes 4 and 5 by intermediate desilylation in a one‐pot fashion. Based upon the catalytic generation of pentadiynones and pyrazolyl‐triazoles thereof [27b] and 1 H ‐1,2,3‐triazol‐4‐yl‐pyrrolo[2,3‐ b ]pyridines, [27a] both in a consecutive one‐pot fashion, the ADAC one‐pot sequence was conceptualized to begin with an alkynylation of an ortho ‐iodo aniline 1 with TIPS‐butadiyne ( 2 ) furnishing the coupled butadiyne 4 . Thereof, desilylation and alkynylation uniquely generate the unsymmetrically substituted butadiyne 5 , which in turn cycloisomerizes by two‐fold base‐mediated 5‐ endo ‐ dig cyclization to furnish the title compounds 3 .…”

Sequentially Pd/Cu‐Catalyzed Alkynylation‐Oxidation Synthesis of 1,2‐Diketones and Consecutive One‐Pot Generation of Quinoxalines

“…Starting from terminal alkynes we developed sequentially metal‐catalyzed multicomponent reactions, particularly for synthesizing heterocycles in a one‐pot fashion . As a key transformation, Sonogashira coupling readily gives an access to alkynes, alkynones, and butadiynes as reactive functional groups that are directly transformed into heterocycles and functional materials . As a consequence we now reasoned that in situ generation of internal alkynes could excellently be concatenated with their oxidation to benzil derivatives and, hence, a novel entry to multicomponent synthesis.…”