Blanchet J, Macklin T, Ang P, Metallinos C, Snieckus V. DirectedOrthoMetalation−Cross Coupling Strategies.N-Cumyl Arylsulfonamides. Facile Deprotection and Expedient Route to 7- and 4,7-Substituted Saccharins⊥.
J Org Chem 2007;
72:3199-206. [PMID:
17385915 DOI:
10.1021/jo062385v]
[Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
By using the powerful N-cumylsulfonamide directed metalation group (DMG), a series of 2-substituted derivatives were prepared according to the directed ortho metalation (DoM) tactic (Table 1). Mild conditions for N-decumylation and other simple transformations of the products have been achieved (Scheme 2). The 3-silyloxy sultam 12 undergoes further DoM to give formyl, thiomethyl, iodo, and amide derivatives 13a-g of potential value for saccharin synthesis (Table 2). An effective route to target 7-aryl saccharins via Suzuki cross coupling (Table 3) followed by further metalation-carbamoylation and cyclization (Table 5) is described. 4,7-Disubstituted saccharins have been obtained by similar sequences (Scheme 3). Mild TFA-mediated N-decumylation furnishes substituted primary arylsulfonamides (Table 4).
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