A facile rearrangement of N-alkyl, N-(0 or p-nitrophenylsulfonamide)-α-amino esters

The Truce–Smiles rearrangement and related reactions: a review

“…9 Gravimetric analysis of the extruded sulfur dioxide, via the formation of BaSO 4 , was exploited base-H + as a convenient method for measuring reaction rates in kinetic studies of these reactions. 15 The tandem Truce-Smiles rearrangement -sulfur dioxide extrusion [34][35][36][37][38][39][40][41][42][43] sequence is likely a common combination, because the sulfonyl group is a useful substituent on the migrating aryl ring that can serve as both an activating group for stabilizing the Meisenheimer adduct by withdrawing electron density through an inductive effect and as a competent leaving group. This is discussed further in section 4.1.…”

“…In the rearrangement of sulfonamides, the rearranged product is typically isolated as an amine following tandem extrusion of sulfur dioxide 35,[38][39][40]42,43 or, in the case of sulfonate, as an alcohol. 36,37 This type of reaction sequence was discussed in section 2.1.1., with an illustrating example shown in Scheme 7.…”

“…58,61 Examples of Truce-Smiles rearrangements occurring through the formation of 4-membered ring spirocyclic Meisenheimer adducts are also relatively uncommon. 36,39,48,52,95 Each of the examples shown in Fig. 7 arise from isolated, seemingly adventitious, observations from a variety of research groups, making it difficult to draw conclusions from these non-systematic, inconsistent examples.…”

“…Putative reported 4-membered ring spirocyclic Meisenheimer adducts. 36,39,48,52,95 Alternative methods for generating the carbanion nucleophile, which has seen some popular use in the Truce-Smiles rearrangement, have been directed-ortho metalation, 58,61,96,100,111 or lithiumhalogen exchange. 95,96 As well, the use of benzyne 43,112 or alkyne 102 intermediates in the generation of aryl anions has been employed in several reports and, in one example, the use of a phenolate anion.…”

Synthesis of nitroaryl derivatives of glycine via oxidative nucleophilic substitution of hydrogen in nitroarenes

“…Synthesis of such nitroarylated glycines are reported via the Strecker reaction, 5 and the base-induced Smiles rearrangement of Nnitrophenylsulfonyl amino acids. 6 In a few earlier papers we reported synthesis of some α-nitroaryl-α-amino acids via oxidative nucleophilic substitution of hydrogen (ONSH) in nitroarenes with carbanions of protected esters of amino acids. The ONSH reaction, a two-stage process, comprises addition of nucleophilic agents such as carbanions to nitroarenes in the ortho or para position, in relation to the nitro group, occupied by hydrogen to form σ H adducts and their subsequent oxidation by an external oxidant.…”