Palladium-Catalyzed Decarboxylative Allylation/Wittig Reaction: Substrate-Controlled Synthesis of C-Vinyl Glycosides

Abstract

A palladium-catalyzed one-pot Tsuji-Trost type decarboxylative allylation/Wittig reaction has been developed to synthesize C-vinyl glycosides. Screening of various aldehydes led to formation of β,(E)-selective C-vinyl glycosides with pyridyl group containing aldehydes and β,(Z)-selective C-vinyl glycosides with nonpyridyl aldehydes. A plausible mechanism is proposed based on the coordination effect of the aldehydes.

Intramolecular and Ferrier Rearrangement Strategy for the Construction of C1‐β‐d‐xylopyranosides: Synthesis, Mechanism and Biological Activity Study

“…For example, Ernest's group utilized Pd 0 ‐mediated cyclo‐etherification of 1‐acetoxy‐2,3‐dideoxy‐oct‐2‐enitols to produce C‐vinyl α ‐ and β ‐glycopyranosides with high stereoselectivity using ( S , S ) or ( R , R )‐DACH ligands in 2014 (Scheme ), and then Martin's group produced epimeric mixture of C‐vinyl deoxyriboside by the Lindlar hydrogenation of the epimeric mixture of C‐ethynyl deoxyriboside . Liu's group reported a palladium‐catalyzed one‐pot Tsuji‐Trost type decarboxylative allylation/Wittig reaction to synthesize β ,( E )‐selective C‐vinyl glycosides with pyridyl group containing aldehydes and β ,( Z )‐selective C‐vinyl glycosides with nonpyridyl aldehydes in 2017, which had potential to be applied in synthesizing C‐vinyl glycosides in high efficiency with controlled diastereoselectivity …”

“…Therefore, the synthesis of C-glycosylation usually involves the metal reagents as glycosyl donors or catalysts, and the process is much more sluggish due to the air and moisture sensitivities. [13] For facial construction of synthetically valuable complex C-glycosides, the intramolecular rearrangements including Claisen rearrangement, Ramberg-Bä cklund rearrangement, and 1,2-Wittig rearrangement have become powerful tools for the C-glycosylations. [10] For example, Ernest's group utilized Pd 0mediated cyclo-etherification of 1-acetoxy-2,3-dideoxy-oct-2-enitols to produce C-vinyl a-and bglycopyranosides with high stereoselectivity using (S,S) or (R,R)-DACH ligands in 2014 (Scheme 1), [11] and then Martin's group produced epimeric mixture of C-vinyl deoxyriboside by the Lindlar hydrogenation of the epimeric mixture of C-ethynyl deoxyriboside.…”

Homogeneous Catalysis: A Powerful Technology for the Modification of Important Biomolecules

“…An efficient andgeneral approach for the synthesis of C-vinyl glycosides 34 that involved ap alladium-catalyzed one-potT suji-Trost allylation/Wittig reaction was reported by Liu and co-workers. [39] Various glycals 29,P -ylides 32, and aldehyde 33 delivered the corresponding C-vinyl glycosides 34 in good-to-excellent yields (Scheme 9). Coordinating pyridyl aldehydes gave C-vinyl glycosides with b-E-selectivity, whereas b-Z-selectivity waso bserved with nonpyridyl aldehydes.…”

“…Interestingly, (3 R )‐glycals gave the products with high selectivities, whilst mixtures of isomers were obtained with (3 S )‐glycals. An efficient and general approach for the synthesis of C ‐vinyl glycosides 34 that involved a palladium‐catalyzed one‐pot Tsuji–Trost allylation/Wittig reaction was reported by Liu and co‐workers . Various glycals 29 , P‐ylides 32 , and aldehyde 33 delivered the corresponding C ‐vinyl glycosides 34 in good‐to‐excellent yields (Scheme ).…”

Iridium-promoted deoxyglycoside synthesis: stereoselectivity and mechanistic insight

“…During recent years, transition metals have played an important role in the chemical synthesis of oligosaccharides, with a flow of intriguing glycosylation methodologies involving a variety of transition metal catalysts reported. 4–16 Conceptually, by installing specific substituents onto the donors 6 and/or control of the oxidation state of the transition metal in the catalysts, face-selective coordination of the catalytic metal complex with the olefinic pyranose ring can be feasibly achieved, 7 enabling stereoselective construction of glycosidic linkages. Additionally, glycal donors can be activated with a catalytic amount of the transition metal catalyst, while in conventional acid or base promoted glycosylation reactions, saturated glycosyl donors consume stoichiometric amounts of activating agents.…”