Preparation of tetrahydroindolizines from pyridinium and isoquinolinium ylides

Abstract

Carbonyl-and nitrite-stabilised pyridinium and cyclic azonium methylides condense with chalcones to form tetrahydroindolizines and analogous fused pyrrolidines. The stereochemistry is illuminated by IsC and l H n.m.r. spectroscopy. Several incorrect literature structures are rectified.c

Alkaloid inspired spirocyclic oxindoles from 1,3-dipolar cycloaddition of pyridinium ylides

“…Starting materials for this route are readily accessible by olefination of isatin to give 3-alkylidene-2-oxindoles; 12 † pyridinium salts were obtained by alkylation. 13 † Pyridinium salts featuring N-methylene groups attached to an electron withdrawing group can be readily deprotonated using mild base to give the ylide. 14,15 Initially, we set out to briefly investigate the role of solvent and base on yield.…”

Convenient Synthesis of Spiro[benzo[d]pyrrolo[2,1‐b]thiazole‐3,2′‐indenes] Derivatives via Three‐Component Reaction

“…[4][5][6][7][8][9][10] Heterocyclic nitrogen ylides have been extensively used in 1,3-dipolar cycloaddition for synthesis of the various nitrogen-containing heterocycles such as polysubstituted pyridines, terpyridines and indolizines. [11][12][13][14][15][16] For this propose, various reactive alkenes, alkynes and other reagents having multiple bond were employed in the 1,3-dipolar cycloaddition reactions. [17][18][19][20][21][22][23][24][25][26] The readily accessible 2-arylideneindane-1,3-diones are highly reactive alkenes and have been used extensively as substrates in the synthesis of spirocyclic indane derivatives, which are important structural units of many naturally occurring biologically active substances.…”

Formation of diverse polycyclic spirooxindoles via three-component reaction of isoquinolinium salts, isatins and malononitrile

“…Because of cyclic nitrogen N -ylides have heterocyclic aromatic character, basicity, electron-attracting positive nitrogen atom, and the strongly electron-withdrawing substituent like carbonyl, cyano, or nitro groups connecting with methylene group, they have been become one of practical potential synthons in synthetic reactions9101112131415161718. The most common reaction is 1,3-dipolar cycloaddition of cyclic nitrogen N -ylides such as pyridinium ylide with various electron-deficient acetylene and alkenes to give indolizine derivatives, in which the pyridyl ring is retained1920212223242526.…”