Reductive cleavage of sulfonates. Deprotection of carbohydrate tosylates by photoinduced electron transfer

Abstract

Esters of p-toluenesulfonic acid are used as protecting groups

The Photochemistry of N‐p‐Toluenesulfonyl Peptides: The Peptide Bond as an Electron Donor

“…The tosylamido chromophore has its least energetic electronic transition near 265 nm with an apparent 0–0 component at 273 nm. This corresponds to 4.54 eV, and with E (red) ∼−2.3 V for tosylamido (19) and application of the Weller equation (53) is seen to provide the excited state with more than enough driving force (over‐potential > (−) 0.7 V) for amide oxidation ( E (ox) ∼ 1.5 V [54]). Effectively, the excited tosylamido chromophore accepts an electron from the carboxamide moiety and products arise from collapse of the charge‐separated intermediate via a choice of competing pathways influenced by substrate structure.…”

Photochemical Cleavage Reactions of 8-Quinolinyl Sulfonates in Aqueous Solution

“…Masanovi et al concluded that this photoreaction requires electron donors such as hydroxide or DABCO (1,4-diazabicyclo[2,2,2]octane), as shown in Chart 5. 18,19) It was generally assumed that the S-O bond of the radical anion 26…”

“…53) Effect of Electron Donor (Et 3 N) Masanovi's group and other groups reported that sulfonyl esters or sulfonamide derivatives undergo photolysis via intramolecular electron transfer 21,22,30) or intermolecular electron transfer. [18][19][20]31) As described above, the effect of substituent groups on the benzenesulfonyl moiety on the kinetics of the photolysis of 5a-d was negligible ( Table 1), indicating that intramolecular photoinduced electron transfer between two aromatic rings of 5a is a minor pathway.…”

“…In the photolysis of 22 and 26, the arenesufonyl groups are excited. [17][18][19][20] In addition, in the photolysis of 29, the arenesulfonyl and aryloxy groups are excited. 23,24) On the other hand, the photolysis of our substrate 5-8 is triggered by excitation of the 8-quinolinyl group, which may alter the reaction pathway.…”

“…; protection/deprotection in organic synthesis [1][2][3][4] and uncaging of chemically masked or caged molecules). [5][6][7][8][9][10][11][12][13] To date, the photolysis of sulfonic esters, [14][15][16][17][18][19][20][21][22][23][24] sulfonamides, [25][26][27][28][29][30][31][32] and sulfones 33,34) has been applied to photoresist materials, 15,26) protecting groups, 8,19,20,[27][28][29][30][31][32] and other chemical reactions. 14,[35][36][37] Based on the above findings, the development of new photocleavage reactions of sulfonic acid derivatives and related mechanistic ...…”