Vittoria Lupi

N-Monoalkylation of α-Amino Acid Esters under Solid-Liquid PTC Conditions

N-(2-Nitrophenylsulfonyl)- (o-NBS-AA-OMe, 4) and N-(4-Nitrophenylsulfonyl)-α-amino acid methyl esters (p-NBS-AA-OMe, 5) were N-alkylated with a variety of alkyl halides 6 under solid-liquid phase-transfer catalysis (SL-PTC) conditions, affording the alkylated products o-NBS-N-R2-AA-OMe 7 and p-NBS-N-R2-AA-OMe 8 in excellent yields without any detectable racemization.

Complementary heterogeneous/homogeneous protocols for the synthesis of densely functionalized benzo[d]sultams: C-C bond formation by intramolecular nucleophilic aromatic fluorine displacement.

Polyfunctionalized benzo[d]sultams 7 and 8, which contain an alpha-amino acid unit, have been synthesized from the corresponding open chain (pentafluorobenzene)sulfonamides 4 by complementary solid-liquid phase transfer catalysis (SL-PTC) and homogeneous protocols. The cyclization step proceeds through the intramolecular nucleophilic displacement of an aromatic fluorine atom.

Environmentally benign, sequential synthesis of 3,4-dihydro-2H-1,4-benzoxazines under phase transfer catalysis conditions

An environmentally friendly synthesis of 2-substituted 3,4-dihydro-2H-1,4-benzoxazines has been carried out in a sequential fashion through the R4N+F− catalyzed ring opening of epoxides with arylsulfonamides, followed by in situ cyclization of the hydroxysulfonamides thus obtained with NaOH aq. and n-C14H29N+Me3Cl−.