Ylide mediated carbonyl homologations for the preparation of isatin derivatives

Abstract

An exceptionally mild method for the preparation of isatin derivatives has been developed using a sulfur ylide mediated carbonyl homologation sequence starting from anthranilic acid precursors. This method proceeds at ambient temperature via a sulfur ylide intermediate without the need for protection of the amine or chromatographic isolation of the intermediate ylide. Gentle oxidation of the sulfur ylides provides isatin derivatives with N-H, N-alkyl, N-aryl substitution, electron-rich and electron-poor aromatic rings, and heterocyclic aromatic systems. We anticipate that this method will greatly expand the accessibility of complex isatin derivatives.

Titania‐Supported Gold Nanoparticles as Efficient Catalysts for the Oxidation of Cellobiose to Organic Acids in Aqueous Medium

“…Subsequently, a series of methods for transition‐metal‐catalyzed C–H oxidation were documented,9 including the copper‐catalyzed intramolecular oxidative C(sp 3 )–H amidation of 2‐aminoacetophenones,9a the copper‐mediated C–H oxidation and C–N cross‐coupling of 2′‐aminoacetophenones,9b as well as oxidative palladium‐catalyzed CH/NH double carbonylation 9c. Furthermore, several other protocols have been established, including ylide‐mediated carbonyl homologations,10 selenium‐mediated oxidations,11 modified Sandmeyer reactions,12 I 2 ‐catalyzed synthesis of isatins from 2′‐aminoacetophenones,13a and I 2 ‐mediated oxidative amidation of sp, sp 2 , and sp 3 C–H bonds 13b…”

Cyanomethyl anion transfer reagents for diastereoselective Corey–Chaykovsky cyclopropanation reactions

“…The analytical data is consistent with the literature. [2] (1R,2R,3R)-2-nitro-3-phenylcyclopropane-1-carbonitrile (7a)…”

“…Compound 10a was prepared according to general procedure and was obtained after column chromatography (n-pentane : diethyl ether 20:1 à 9:1 à 4:1) as a colorless oil in 90% yield (31 mg 2,136.3,134.2,129.1,128.5,120.0,24.2,17.0,7.5 ppm;HRMS (ESI): mass found: 194.05780, calculated mass for C 11 H 9 NNaO + : 194.05764; IR (KBr): 3055, 2925, 2854, 2664, 2329, 2244, 2090, 1996, 1954, 1917, 1819, 1673, 1595, 1494, 1448, 1395, 1303, 1224, 1180, 1066, 1012, 912, 853, 813, 771, 697 cm -1 . The analytical data is consistent with the literature.…”

Copper-Catalyzed Aerobic Oxidation Strategy: A Concise Route to Isatin

“…In view of this, new synthetic methods to overcome these drawbacks are still highly required. Inspiringly, some efficient methods have been found, such as aryne-based methods, [6] transition-metal catalyzed oxidation, [7] oxidative cleavage of carbon-carbon triple bond, [8] sulfur ylide-mediated carbonyl homologation, [9] iodine-mediated oxidation, [10] and C-H amination (Scheme 1). [11] Although these methods showed some im-provements, there are still many problems like the requirement of heavy metal catalysts and excess amount of bases or strong oxidants and relatively low yields of products.…”