Efficient Synthesis of 3,3′-Mixed Bisindoles via Lewis Acid Catalyzed Reaction of Spiro-epoxyoxindoles and Indoles

Abstract

An efficient strategy for the synthesis of 3-(3-indolyl)-oxindole-3-methanol has been developed to achieve a Lewis acid catalyzed, highly regioselective ring opening of spiro-epoxyoxindoles with indoles. The method is used for the gram-scale formal total synthesis of (±)-gliocladin C.

The Epoxidation of Carbonyl Compounds with a Benzyne-Triggered Sulfur Ylide

“…36 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 255.1015. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ASSOCIATED CONTENT…”

Enantioselective synthesis of mixed 3,3′-bisindoles via a phosphine-catalyzed umpolung γ-addition of 3′-indolyl-3-oxindoles to allenoates

“…Compound 7 then underwent a three-component reaction with benzoyl hydrazine and TMSCN to afford a-aminonitirile 8 in a highly diastereoselective manner. Finally, hydrolysis and reductive cyclization furnished compound 9, the core structure of Gliocladin C and its related nature product family [81][82][83][84][85][86][87] (Scheme 5).…”

Regioselective Alcoholysis and Hydrochlorination Reactions of Spiro‐Epoxy Oxindoles at the Spiro‐Centre: Synthesis of 3,3‐Disubstituted Oxindoles and Application for Anticancer Agents

“…The Bi III species coordinates to the oxygen atom of epoxide and also interacted with the carbonyl oxygen of the spiro‐epoxy oxindole to activate the epoxide ring [1], followed by an attack of MeOH [2] and generate an active indolone intermediate [3]. Subsequently, the ring opened intermediate would then undergo a quick proton transfer to assist the regeneration of Bi III catalyst and the desired alkyloxy product , …”

“…spiro‐epoxy oxindole to 3,3‐disubstituted oxindoles by the ring opening at spiro center with various nucleophiles is foremost and straightforward strategy to get a large number of natural products and pharmaceutical agents like flustramine A, arundaphine, CPC‐1, donaxaridine, (–)‐horsfiline and class of welwitindolinones [Figure ]. Hence, many research groups across the world have started to work in this vital area of research . Considering the widespread importance and huge applications of 3,3‐disubstituted oxindole molecules and also in the continuation of our ongoing research work in the epoxide chemistry, herein, we are reporting an efficient and straightforward synthesis of novel heterocyclic molecules viz., 3‐hydroxymethyl‐3‐alkyloxy‐oxindole and 3‐chloro‐3‐(hydroxymethyl)oxindole via regioselective ring opening of spiro‐epoxy oxindoles with alcohols and chlorine respectively by using Bismuth trichloride (BiCl 3 ) as active Lewis acid catalyst .…”