Flexible Synthesis of 2‐Deoxy‐C‐Glycosides and (1→2)‐, (1→3)‐, and (1→4)‐Linked C‐Glycosides

Abstract

Link! Two, three, four! A rapid and flexible synthesis of native (1→n)‐linked C‐disaccharides (n=2, 3, 4; left) is possible. The configuration of the pseudoanomeric carbon was readily established by an epoxidation/ring‐opening sequence. The synthesis of (1→n)‐linked 2‐deoxy‐C‐disaccharides (right) with high diastereoselectivity follows an even shorter route.

Modular Stereoselective Synthesis of (1→2)‐C‐Glycosides based on the sp2–sp3 Suzuki–Miyaura Reaction

“…These methods are, however, developed only for specific linkages (1→6, 1→4, 1→3, or 1→2) and require multistep reaction sequences and in some cases complex starting materials that are not readily available. Recently, the Werz group introduced two modern Sonogashira [4 h] and Stille4e cross‐coupling reactions into carbohydrate chemistry, allowing for preparation of different (1→2, 1→3, 1→4, 1→6)‐linked C ‐disaccharides from relatively simple saccharide subunits.…”

“…The corresponding α‐ C ‐linked mimetics of natural disaccharides α‐ D ‐Glc p ‐(1→2)‐α‐ D ‐Man p OMe 17 and α‐ D ‐Man p ‐(1→2)‐α‐ D ‐Man p OMe 20 were obtained by epoxidation of the double bond with dimethyldioxirane18 (DMDO), followed by subsequent cleavage of the formed epoxide ring with lithium triethylborohydride (Super‐hydride) 4e. h, 15, 19 The successful isolation of derivative 16 (69 %) strongly depended on the oxidative decomposition of excess of Super‐hydride with alkaline hydrogen peroxide (see the Supporting Information).…”

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

“…To install the anthraquinone moiety it was necessary to reprotect the alcohol functionalities. It has proven challenging to install the TBS protecting group at the substrates, particular for the galactose-derived derivatives 12b which could be obtained in only poor yield [47–49]. For 27a the FeCl 3 -catalyzed benzylic oxidation proceeded smoothly with yields of up to 70% [50].…”

β‐Selective C‐Glycosylation and its Application in the Synthesis of Scleropentaside A

“…[1] Widely employed methods for the synthesis of C-glycosides are reactions of glycosyl donors with nucleophiles in the presence of Lewis acids.M ost of these methods yield predominantly the a-anomeric C-glycosides [4] or require the use of heavy-metal organometallic reagents or catalysts in the CÀC-bond forming step. [5] Furthermore,amultitude of these synthesized C-glycosides are arylated at the anomeric position, which can be achieved by various cross-coupling reactions of glycals with arylhalogens [6] or Grignard reagents [7] So far,a nomeric acyl-b-C-glycosides 5 have been synthesized via nitrile 3, [8] which can be obtained in three steps starting from the carbohydrate 2 (Scheme 2). [9] Furthermore, aCorey-Seebach reaction [10] of acarbohydrate to yield lactol 4,w hich had to be reduced subsequently,h as also been reported.…”