Thiomaleic Anhydride: A Convenient Building Block for the Synthesis of α-Substituted γ- and δ-Lactones through Free-Radical Addition, Nucleophilic Ring Opening, and Subsequent Thiocarboxylate Manipulation
作者:David Crich、Md. Yeajur Rahaman
DOI:10.1021/jo901219k
日期:2009.9.4
carbonates and carbamates undergo clean free-radical addition to thiomaleic anhydride to give substituted thiosuccinic anhydrides in high yield on treatment with tris(trimethylsilyl)silane and a radical initiator. After removal of the tert-butyloxycarbonyl group, cyclization then affords lactones or lactams substituted in the α-position by a thiocarboxylic acid residue. This group is converted to amides through
Temperature dependent reaction pathways in the addition of silyl, germyl, stannyl and plumbyl radicals to maleic anhydride and related compounds: an ESR study
The addition of GroupIVB organometallic radicals to maleic anhydride, maleic thioanhydride, maleimide and N-methyl maleimide has been investigated by ESR spectroscopy. For Si and Ge centred radicals the reaction pathway has been found to be temp dependent, the addition of the organometallic radical occurring at the CC double bond at lower temps at either of the two CO groups at higher temps. For Sn
Cyclic Thioanhydrides: Linchpins for Multicomponent Coupling Reactions Based on the Reaction of Thioacids with Electron-Deficient Sulfonamides and Azides
作者:David Crich、Albert A. Bowers
DOI:10.1021/ol702570x
日期:2007.12.1
electron-deficient azides or, preferably, 2,4-dinitrobenzenesulfonamides. In this manner the cyclic thioanhydride serves as a linchpin in a three-componentcouplingsequence. The use of thiomaleic anhydride and a bifunctional nucleophile extends the process to heterocycle synthesis, while a cyclic thioanhydride prepared from aspartic acid directly provides N-functionalized asparagine derivatives.