343565-52-6Relevant academic research and scientific papers
Palladium-Catalyzed C-S Bond Formation as a Tool for Latent-Active Glycosylation
Hedberg, Christinne,Jessen, Kamilla S.,Hansson, Rikke F.,Heuckendorff, Mads,Jensen, Henrik H.
, p. 7068 - 7072 (2020)
A high-yielding palladium-catalyzed C-S cross-coupling is presented for utilization in carbohydrate chemistry as a key transformation for attachment of a second chelating sulfur atom that allows the exploitation of a latent-active glycosylation strategy w
AuCl3-AgOTf promoted O-glycosylation using anomeric sulfoxides as glycosyl donors at room temperature
Palanivel, Ashokkumar,Chennaiah, Ande,Dubbu, Sateesh,Mallick, Asadulla,Vankar, Yashwant D.
, p. 43 - 49 (2016/12/09)
Activation of sulfoxide as glycosyl donors using AuCl3/AgOTf reagent system has been described. Under optimal reaction conditions, both armed and disarmed glycosyl sulfoxide donors were found to react with a range of primary, secondary, and tertiary alcohol acceptors, and sugar derived glycosyl acceptors to afford the corresponding glycosides in moderate to good yields with predictable selectivity. The reactions are quick (20–60 min), facile at room temperature and the reactions conditions tolerate acid sensitive groups.
Glycosyl ortho-Methoxybenzoates: Catalytically Activated Glycosyl Donors with an Easily Removable and Recyclable Leaving Group
Kristensen, Steffan K.,Salamone, Stéphane,Rasmussen, Michelle R.,Marqvorsen, Mikkel H. S.,Jensen, Henrik H.
, p. 5365 - 5376 (2016/11/22)
We describe the β-ortho-methoxybenzoate as a shelf stable and practical C-1 nucleofuge for catalytic chemical glycosylation in which the benzoic acid by-product can be easily removed, reisolated, and potentially recycled after the glycosylation reaction. This new type of glycosyl donor can be efficiently activated by a range of promoters, including Bi(OTf)3, Fe(OTf)3, TMSOTf (TMS = trimethylsilyl), and triflic acid, with low (10 mol-%) catalyst loadings. The donor shows higher reactivity than analogous benzoate, p-methoxybenzoate and p-cyano-o-methoxybenzoate donors. In glycosylation reactions with o-methoxybenzoate donors, the yields of disaccharide products were good to excellent for various glycosyl acceptors, including a carbohydrate-based secondary alcohol. Furthermore, β-selective mannosylation was achieved with a Crich-type donor at 0 °C to ambient temperature, without donor preactivation. The donor was also used for the first step of a one-pot two-step glycosylation to obtain a trisaccharide; the second coupling involved activation of a thioglycoside with NIS/TMSOTf (NIS = N-iodosuccinimide). We believe that this offers a good alternative to current protocols.
Remote Electronic Effects by Ether Protecting Groups Fine-Tune Glycosyl Donor Reactivity
Heuckendorff, Mads,Poulsen, Lulu Teressa,Jensen, Henrik H.
, p. 4988 - 5006 (2016/07/06)
It was established that para-substituted benzyl ether protecting groups affect the reactivity of glycosyl donors of the thioglycoside type with the N-iodosuccinimide/triflic acid promoter system. Having electron donating p-methoxybenzyl ether (PMB) groups increased the reactivity of the donor in comparison to having electron withdrawing p-chloro (PClB) or p-cyanobenzyl ether (PCNB) protecting groups, which decreased the reactivity of the glycosyl donor relative to the parent benzyl ether (Bn) protected glycosyl donor. These findings were used to perform the first armed-disarmed coupling between two benzylated glucosyl donors by tuning their reactivity. In addition, the present work describes a highly efficient palladium catalyzed multiple cyanation and methoxylation of p-chlorobenzyl protected thioglycosides. The results of this paper regarding both the different electron withdrawing properties of various benzyl ethers and the efficient and multiple protecting group transformations are applicable in general organic chemistry and not restricted to carbohydrate chemistry.
An α-selective, visible light photocatalytic glycosylation of alcohols with selenoglycosides
Spell, Mark,Wang, Xiaoping,Wahba, Amir E.,Conner, Elizabeth,Ragains, Justin
, p. 42 - 47 (2013/05/08)
Exceptionally mild procedures for the visible light photocatalytic activation of selenoglycoside donors in the presence of alcohol acceptors have been developed. This process is demonstrated with both 1-phenylselenyl-2,3,4,6- tetra-O-benzyl glucoside (1) and 1-phenylselenyl-2,3,4,6-tetra-O-benzyl galactoside (2). Catalysis is effected with both metal (Ru(bpy)3) and organocatalysts (diphenyldiselenide). Reactions afford, in all cases, primarily the α-anomers with selectivities that vary with solvent. This represents the first example of a visible light-promoted O-glycosylation.
