Glycosylation with 3,5-Dimethyl-4-(2′-phenylethynylphenyl)phenyl (EPP) Glycosides via a Dearomative Activation Mechanism

Abstract

A highly effective and versatile glycosylation method is developed, which uses 3,5-dimethyl-4-(2′phenylethynylphenyl)phenyl (EPP) glycosides as donors and NIS/TMSOTf as promoter and proceeds via an unprecedented dearomative activation mechanism.

A Mild Glycosylation Protocol with Glycosyl 1‐Methylimidazole‐2‐carboxylates as Donors

“…Glycosylation of acceptor 6 e (10 mg, 0.064 mmol) with donor 3 a (59 mg, 0.084 mmol) using the General Glycosylation Procedure afforded glycoside 7 h (petroleum ether/ethyl acetate=6/1; 40 mg, 85 %) as colorless syrup. The 1 H NMR spectral data of 7 h are identical with the literature data [27] …”

Glycosyl ortho-(1-phenylvinyl)benzoates versatile glycosyl donors for highly efficient synthesis of both O-glycosides and nucleosides

“…In comparison, using Yu glycosylation with glycosyl ABz, nucleosides 6a, 6b, and 6c were obtained in 85%, 88%, and 95% yields, respectively 36 . Using EPP glycosides, 6a and 6c were produced in 90% and 91% yields, respectively 37 . The other furanosyl donors 1k and 1m-n including L-arabino, D-galacto-, and even D-fructofuranosyl donors were also coupled efficiently with nucleobases 5a, 5c, and 5e, providing the corresponding nucleosides 6f-h in excellent yields (91-96%).…”

“…It was noted that N-glycosylation of purines using Yu glycosylation with glycosyl ortho-alkynylbenzoates afforded N9 nucleosides 6o, 6p, 6q, and 6u in 77%, 84%, 80%, and 48% yield, respectively 36 . Using EPP glycosides, the corresponding 6o, 6q, and 6u were prepared in 74%, 73%, and 69% yields, respectively 37 .…”

Route efficiency assessment and review of the synthesis of β-nucleosides via N-glycosylation of nucleobases

“…The same strategy and conditions can also be employed with ( phenylethynylphenyl)phenyl glycosides as alternative leaving groups (Scheme 7). 66…”