Orthogonality and compatibility between Tsc and Fmoc amino-protecting groups

Bioinspired Design and Oriented Synthesis of Immunogenic Site-Specifically Penicilloylated Peptides

“…After stirring at reflux for 3 h, the reaction mixture was concentrated to give compound 2a as a cream solid which was used in the following step without purification (410 mg, 98%); 1 H NMR (CD 3 OD, 300 MHz) δ 1.30–2.00 (m, 6H, (CH 2 ) 3 ), 2.93 (m, 2H, CH 2 ), 3.73 (s, 3H, COO CH 3 ), 4.10–4.50 (m, 4H, CH, CH CH 2 Fmoc, CH 2 Fmoc), 7.20–7.50 (m, 4H, CHar ), 7.70 (m, 2H, CHar ), 7.81 (d, 3 J = 7.5 Hz, 2H, CHar ); IR (cm –1 ) ν max 3304, 2949, 2862, 1727, 1690, 1546. Experimental data are in accordance with the literature. , …”

MgI2‐Mediated Chemoselective Cleavage of Protecting Groups: An Alternative to Conventional Deprotection Methodologies

“…In particular, the exploitation of the orthogonal stabilityp rinciple allows condition-dependent elimination of defined PGs, Fmoc/tBu, or Boc/ Bzl, whicha re probablyt he most popular couples to illustrate this concept. Several orthogonald eprotection processesh ave been described, [1][2][3] thougha ne xamination of the literature still highlights some gaps in chemoselective flexibility or limitations due to harsh cleavage conditions.I ndeed, the development of am ild, clean, and selectivem ethodf or deprotection would be aw elcomesynthetic strategy.In this context, we offer an exceptionally simple, quantitative, and chemoselective process.B yd emonstrating how to efficiently preserveaFmoc moiety (one of the most popular base-labile N-terminal PGs) whilep erforming an ester cleavage, simple but mostly unreturned questionsi nP Gs strategies were then solvable, that is, how to cleave ab enzyloxycarbonyl( Z) while keeping benzyl ethers, an allyl, or an alloc in ap alladium-freeprocess, or even how to remove apeptidefrom aMerrifield resin underm ild conditions. Thoughexperimental procedures to remove aF moc usually do not affect esters, the opposite chemoselectivity is not obvious…”