An enantioselective organocatalytic addition of sodium bisulfite to (E)‐nitroalkenes has been developed by using a chiral bifunctional organocatalyst. The present methodology provides a variety of chiral β‐nitroethanesulfonic acid compounds (17 examples) with excellent results: up to 99 % yield and excellent enantioselectivity (up to 96 % ee). The reaction tolerates (hetero)aryl and alkyl substituents on the β‐nitroalkenes, and β,β‐disubstituted nitroalkenes.
A metal-free oxidative C(sp3)–N coupling process has been developed for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones. The reaction between primary amines, isatoic anhydride, and benzylic alcohols in the presence of HBr in DMSO at 80 °C affords 2,3-dihydroquinazolin-4(1H)-ones in excellent yields. Under these reaction conditions, benzylic alcohols react with in situ generated bromodimethylsulfonium bromide to form alkoxysulfonium intermediates. These intermediates undergo an oxidative cyclization reaction with primary amines and isatoic anhydride to produce the title products.
Knoevenagel condensation reaction of an aldehyde and Meldrum's acid produces a 5-arylmethylidene Meldrum's acid, which undergoes Michael addition of a trialkyl phosphite under solvent-free conditions to afford the title compounds in good yields.
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