Debenzylation of complex oligosaccharides using ferric chloride

Expeditious Asymmetric Synthesis of a Stereoheptad Corresponding to the C(19)–C(27)‐Ansa Chain of Rifamycins: Formal Total Synthesis of Rifamycin S

“…[24] Alternatively, Evans reduction of aldol (+)-30 followed by treatment with anhydrous FeCl 3 (CH 2 Cl 2 , 08C) [25] and Me 2 C(OMe) 2 /pTsOH provided the bis-acetonide (+)-32 (62 %, overall), the NMR data of which confirmed its structure and has the same configuration as stereoheptad (À)-2. Ozonolysis of (+)-32; subsequent reductive workup gave (À)-2 in 80 % yield (Scheme 6).…”

A Stereoselective Synthesis of (+)‐Piscidic Acid and Cimicifugic Acid L

“…Acid-catalysed removal of the this group with FeCl 3 [22,23] gave the desired compound 11 in 53 % yield; however, a 3:1 mixture of the trans/cis isomers was obtained. The same reaction was carried out with cinnamate ester 12, and, interestingly, only the trans product, phenol 13, was obtained (Scheme 3).…”

Multi gram-scale synthesis of galactothionolactam and its transformation into a galactonoamidine

“…21 Among others, debenzylation reactions of aromatic dibenzyloxy aldehydes and the regioselective debenzylation of monosaccharides and complex oligosaccharides have been achieved by using magnesium bromide, 22 chromium(II) chloride, 23 or iron(III) chloride. 24,25 While in need for mild reaction conditions for the encompassing deprotection of a perbenzylated carbohydrate with an amidine functionality, we explored the use of FeC1 3 in dichloromethane. 25 The FeC1 3 reagent has previously been utilized for the anomerization of glycosides, 26 and for the debenzylation of monosaccharides.…”

“…24,25 While in need for mild reaction conditions for the encompassing deprotection of a perbenzylated carbohydrate with an amidine functionality, we explored the use of FeC1 3 in dichloromethane. 25 The FeC1 3 reagent has previously been utilized for the anomerization of glycosides, 26 and for the debenzylation of monosaccharides. 27 While the debenzylation of 10 proceeds in the presence of 16 equiv of iron(III) chloride without difficulty, 25 the isolation of 1 was found to be tedious in the presence of such large excess of ferric ions.…”

“…25 The FeC1 3 reagent has previously been utilized for the anomerization of glycosides, 26 and for the debenzylation of monosaccharides. 27 While the debenzylation of 10 proceeds in the presence of 16 equiv of iron(III) chloride without difficulty, 25 the isolation of 1 was found to be tedious in the presence of such large excess of ferric ions. ESI mass spectrometry on both the aqueous and the organic layer confirmed the presence of 1 in either layer after aqueous workup of the reaction mixture.…”