High yielding N-transacylation of secondary amides in acids labile molecules by the action of perfluorinated anhydrides in the presence of a mild base

The simple addition of mild bases (Et3N or DIPEA) allows a high yielding N-transacylation of secondary amides, performed by perfluorinated anhydrides, in molecules that are very sensitive to acids.

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(2R,4S,5R,6R,7S,8R)-2-4,7,8,9-Penta-O-acetyl-5-N-(2,2,2-trifluoroacetyl)-β-neuraminic acid methyl esterC22H28F3NO14[α]D25=-22.3 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(2R,4S,5R,6R,7S,8R)-2-4,7,8,9-Penta-O-acetyl-5-N-(2,2,3,3,3-pentafluoropropyonil)-β-neuraminic acid methyl esterC23H28F5NO14[α]D25=-18.5 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(2R,4S,5R,6R,7S,8R)-2-4,7,8,9-Penta-O-acetyl-5-N-(2,2,3,3,3,4,4,4-heptafluorobutanoyl)-β-neuraminic acid methyl esterC24H28F7NO14[α]D25=-22.5 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(2R,4S,5R,6R,7S,8R)-2-Methyl-4,7,8,9-tetra-O-acetyl-5-N-(2,2,3,3,3,4,4,4-heptafluorobutanoyl)-β-neuraminic acid methyl esterC23H28F7NO13[α]D25=+2.0 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(2R,4S,5R,6R,7S,8R)-4,8-Diacetyl-2-benzyloxycarbonyl-9-(2-methoxyethoxy)methyl-N-(2,2,3,3,4,4,4-heptafluorobutanoyl)-β-neuraminic acid 1,7-lactoneC29H32F7NO14[α]D25=+18.1 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(2R,4S,5R,6R,7S,8R)2-Benzyloxycarbonyl-4,8,9-tri-trimethylsilyl-N-(2,2,3,3,4,4,4-heptafluorobutanoyl)-β-neuraminic acid 1,7-lactoneC30H44NO10Si3[α]D25=+69.1 (c 1, CHCl3)Source of chirality: natural sialic acidAbsolute configuration: (2R,4S,5R,6R,7S,8R)

(1R,2R,3R,4S,5R)-Methyl 3,4,6-O-tri-benzyl-2-deoxy-2-N-(2,2,3,3,4,4,4-heptafluorobutanoyl)-α-d-glucopyranoseC32H32F7NO6[α]D25=+58.8 (c 1, CHCl3)Source of chirality: natural d-glucosamineAbsolute configuration: (1R,2R,3R,4S,5R)

(1R,2R,3R,4S,5R)-3,4,6-O-Tri-parametoxybenzyl-2-deoxy-2-N-(2,2,3,3,4,4,4-heptafluorobutanoyl)-α-d-glucopyranoseC35H38F7NO9[α]D25=+2.6 (c 1, CHCl3)Source of chirality: natural d-glucosamineAbsolute configuration: (1R,2R,3R,4S,5R)