Directed ortho metalation reactions. Expedient synthesis of 3,3′-disubstituted 1,1′-bi-(2-phenols) (BIPOLS)
摘要:
Metalation-electrophile quench of the 1,1'-bi-(2-biphenol) bis OCONEt(2) and OMOM derivatives 1a-b provides a general route to 3,3'-disubstituted products 2a-b; dianionic ortho-Fries rearrangement of la furnishes, after acetylation, the 3,3'-bisamide 4 while Suzuki and Negishi cross coupling of 2a (E = I and ZnBr) affords 3,3'-diaryl derivatives 5a-b in good yields.