Pd-Catalyzed Asymmetric Intermolecular Hydroalkoxylation of Allene: An Entry to Cyclic Acetals with Activating Group-Free and Flexible Anomeric Control

Abstract

A ligand-directed metal-catalyzed asymmetric intermolecular hydroalkoxylation of alkoxyallene is reported. Combined with ring-closing-metathesis, this reaction offers a new atom-efficient synthetic method toward various cyclic acetals with elaborate anomeric control. Synthetic utility of the reaction was demonstrated by the atom-efficient and stereodivergent access to various mono- and disaccharides.

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

“…Ar eaction sequence that involved aP d-catalyzed asymmetric intermolecularh ydroalkoxylation reaction, followed by ringclosing metathesis (RCM), was described by Rheea nd co-workers. [31] Thus, hydroalkoxylation of alkoxy allenes 21 with alcohols 20 provided allylic acetals, the RCM of which delivered a diverser ange of mono-and oligosaccharides 23 with excellent diastereo-and enantioselectivities(Scheme 7). Thechiral ligand (22)d ecidedt he stereochemistry at the anomeric center.T his efficient hydroalkoxylation/RCM strategy was furthere xtended to the de novo synthesis of furanose-containingmono-and oligosaccharides.…”

De Novo Synthesis of Mono‐ and Oligosaccharides via Dihydropyran Intermediates

“…In 2014, Rhee et al developed an ovel strategy for de novo carbohydrate synthesis by combining RCMw ith ac hiral-catalyst-promoteda symmetric intermolecularh ydroalkoxylation of alkoxyallenes (Scheme 20). [53] In this case, cyclization of chiral acetalw as realized by the RCM reaction. The stereochemistry of the anomeric centerwas controlled by the chiral catalyst.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…[681]; (3) five-and six-membered ring spirocyclic ethers [682]; (4) six-membered ring ethers, including those employed in syntheses of disaccharides [683], the spiroketal core of spirastrellolide A [684], and a dihydropyranonucleoside (e.g. 264) [685]; (5) six-membered ring α,β-unsaturated lactones, including total syntheses of cryptolactones A1, A2, B1, and B2 (e.g.…”