53941-27-8Relevant articles and documents
Hydrogen-Bonding-Promoted Cascade Rearrangement Involving the Enlargement of Two Rings: Efficient Access to Polycyclic Quinoline Derivatives
Cao, Wen-Bin,Ji, Shun-Jun,Lan, Yu,Li, Haiyan,Li, Shijun,Xu, Meng-Meng,Xu, Xiao-Ping
, p. 21425 - 21430 (2020/09/23)
An efficient cascade reaction of tryptamine-derived isocyanides with C,N-cyclic azomethine imines is described. The polycyclic pyrrolo[2,3-c]quinoline derivatives, which benefited from rearrangement process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40–87 %) under metal-free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N-cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in-depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine-derived isocyanide-based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.
Isocyanide 2.0
Ahmadian-Moghaddam, Maryam,D?mling, Alexander,Patil, Pravin
supporting information, p. 6902 - 6911 (2020/11/09)
The isocyanide functionality due to its dichotomy between carbenoid and triple bond characters, with a nucleophilic and electrophilic terminal carbon, exhibits unusual reactivity in organic chemistry exemplified for example in the Ugi reaction. Unfortunately, the over proportional use of only a few isocyanides hampers novel discoveries about the fascinating reactivity of this functional group. The synthesis of a broad range of isocyanides with multiple functional groups is lengthy, inefficient, and exposes the chemist to hazardous fumes. Here we present an innovative isocyanide synthesis overcoming these problems by avoiding the aqueous workup which we exemplify by parallel synthesis from a 0.2 mmol scale performed in 96-well microtiter plates up to a 0.5 mol multigram scale. The advantages of our methodology include an increased synthesis speed, very mild conditions giving access to hitherto unknown or highly reactive classes of isocyanides, rapid access to large numbers of functionalized isocyanides, increased yields, high purity, proven scalability over 5 orders of magnitude, increased safety and less reaction waste resulting in a highly reduced environmental footprint. For example, the hitherto believed to be unstable 2-isocyanopyrimidine, 2-acylphenylisocyanides and even o-isocyanobenzaldehyde could be accessed on a preparative scale and their chemistry was explored. Our new isocyanide synthesis will enable easy access to uncharted isocyanide space and will result in many discoveries about the unusual reactivity of this functional group. This journal is
