Dip in! A Rh/dippf catalyst generates aldehyde‐derived enol boranes at ambient temperature by isomerization of allyloxy‐ and homoallyloxyboranes. A one‐pot isomerization/cross‐aldol sequence provides aldehyde–aldehyde adducts in good yield with syn selectivity. Direct use of primary allylic and homoallylic alcohols was also achieved.
Rh-Catalyzed AldehydeAldehyde Cross-Aldol Reaction under Base-Free Conditions: In Situ Aldehyde-Derived Enolate Formation through Orthogonal Activation
The chemoselective generation of aldehyde‐derived enolates to realize an aldehydealdehyde cross‐aldol reaction is described. A combined Rh/dippf system efficiently promoted the isomerization/aldol sequence by using primary allylic, homoallylic, and bishomoallylic alcohols; secondary allylic and homoallylic alcohols; and trialkoxyboranes that were derivedfrom primary allylic and homoallylic alcohols