One-pot synthesis of stable heterocyclic phosphorus ylides 4a-j is reported in fairly good yields by the reaction between dialkyl acetylenedicarboxylates and triphenyl phosphite in the presence of strong NH-acids such as 2benzoxazolinone, 2-indolinone and 2-mercaptobenzoxazole in aqueous media as an environmentally friendly solvent. The hydrolysis of compounds 4a-f led to stable phosphonate ester derivatives 5h-l. The configuration of compounds 5h-l (2S * ,3R * ) was determined on the basis of coupling constant predicted from the Karplus equation.
An efficient and simple procedure for the synthesis of novel isatin derivatives is described. Michael addition of aniline Schiff bases of isatin or p‐toluidine Schiff bases of isatin to fumaric esters affords the Michael adduct compounds in good to high yields in the presence of K2CO3 and tetrabutylammonium bromide (TBAB) under solvent‐free conditions. Repeating of this reaction about spiro[1,3‐dioxolane‐2,3′‐indol]‐2′(1′H)‐one, as a Michael donor, in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) gives Michael adducts in remarkable yields under the same conditions.
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