Recent advances in indoline synthesis

Anti-selective [3+2] (Hetero)annulation of non-conjugated alkenes via directed nucleopalladation

“…C atalytic (hetero)annulation [1][2][3][4] of C-C π-systems is a powerful method for constructing carbocyclic and heterocyclic core structures from comparatively simple progenitor compounds. Of special importance within the modern synthetic repertoire is the Pd(0)-catalyzed Larock indole synthesis, first described in 1991 5 , which unites alkynes and 2haloanilines ( Fig.…”

Synthesis of Indolines and Derivatives by Aza‐Heck Cyclization

“…Many of these examples provide indolines bearing fully substituted C2 carbon centers adjacent to nitrogen . As mentioned, this is a motif that appears widely in bioactive natural products but is often challenging to prepare (Figure ) . Benzylic substitution is also well tolerated.…”

“…Using aza‐Wacker approaches, there has been only one isolated example of the formation of a fused bicyclic indoline, and one example of the cyclization to form an indoline bearing a fully substituted C2 carbon center . In general, access to indolines bearing full substitution at C2 is challenging, and most often requires manipulation of a preformed indole core . Tsuji–Trost and related allylation reactions are capable of accessing such molecules; however, they require more highly functionalized allylic electrophiles, which introduces difficulty in starting material preparation and limits the accessible product ring topologies.…”

Diastereoselective Palladium Catalyzed Carbenylative Amination of ortho‐Vinylanilines with 3‐Diazoindolin‐2‐ones

“…[3] Some representative examples of spirooxindole containing natural products and bioactive molecules are shown in Figure 1. [4] In addition, spirocyclic compounds possess unique threedimensional molecular architecture, which is also used as key structural unit in various drug discover. [5] Due to its exceptional conformational rigidity and bio-logical profile, synthesis of spirooxindoles has been a long-standing interest in contemporary organic synthesis.…”

“…Replacing [Pd(cinnamyl)Cl] 2 with PdCl 2 gave the product in 38% yield ( Table 1, entry 3). Further, other Pd-catalysts such as Pd(OAc) 2, Pd(PPh 3 ) 2 Cl 2, Pd(PhCN) 2 Cl 2, Pd(PPh 3 ) 4 were screened, either found diminish in yield of 3 a or reaction was not occurred (Table, entries 4-7). Successively, the best yield of 91% of 3 b was achieved by changing diazo compound 2 a to 2 b (Table 1, entry 8).…”