Diethylaluminum Iodide Promoted Morita–Baylis–Hillman Reaction of D‐Glucose‐Derived Densely O‐Functionalized Cyclopentenone: Route to α‐C‐Branched Densely Functionalized Cyclic Enones

Abstract

Morita–Baylis–Hillman (MBH) reaction of D‐glucose‐derived highly O‐functionalized cyclopentenone is described for the first time. The MBH reaction of cyclopentenone with different aldehydes in the presence of diethylaluminum iodide proceeded smoothly in moderate to good yields. Promoters such as organic, inorganic, or Lewis bases and an aqueous medium are not suitable conditions for the MBH reaction of highly O‐functionalized cyclopentenones with aldehydes.

Synthesis of a Series of γ-Keto Allyl Phosphonates

“…Next, in order to investigate the scope and the limitations of this rapid and efficient synthetic method, we investigated the behavior of a variety of MBH acetates 1b – l toward triethylphoshite or thoxydiphenylphosphine under the conditions listed above (solvent-free conditions, 80 °C). Our results showed that the nucleophilic allylic substitution worked well with six-membered cyclic MBH adducts 1b – g using DMAP or imidazole (Table , entries 2–11) as well as with five-membered cyclic MBH 1h – l using imidazole (Table , entries 12–16), which is usually employed as a powerful nucleophile to mediate various reactions of five-membered cyclic enones . In all cases, we observed that the conversion of the primary acetates 1a and 1h and the secondary acetates 1b – g and 1i – l (R = linear/branched alkyl or aryl) occurred within 30–45 min, affording the corresponding allylic phosphonate or phosphine oxides 2a – p in high to excellent yields (70–93%) (Scheme , Table ).…”

Palladium-Catalyzed Double Allylation of Sugar-Imines by Employing Tamaru–Kimura’s Protocol: Access to Unnatural Iminosugars

“…Sugar lactol 9 required for our strategy was synthesized from Dglucose. 6 Our synthetic endeavor included in situ formation of the N,O-acetal with aniline and sugar lactol 9 in THF followed by treatment with a mixture of Pd(OAc) 2 , n-Bu 3 P, Et 3 B, or Et 2 Zn and allyl alcohol in THF at 50 °C under N 2 atmosphere to give disubstituted heterocycles 10, nucleophilic allylated product 11, and diallylated product 12 (Scheme 3). The reaction was explored under different conditions (see Supporting Information).…”