Synthesis of Bifunctional Monomers by the Palladium‐Catalyzed Carbonylation of Cardanol and its Derivatives

A 1,2‐bis(di‐tert‐butylphosphinomethyl)benzene‐modified palladium catalyst has been used to synthesize bifunctional monomers of different chain lengths from cardanol. Short‐chain derivatives of cardanol, such as (E)‐3‐(dodec‐8‐enyl)phenol; HOPhC12‐ene, (E)‐3‐(undec‐8‐enyl)phenol; HOPhC11‐ene, (E)‐3‐(dec‐8‐enyl)phenol; HOPhC10‐ene, and 3‐(non‐8‐enyl)phenol; HOPhC9‐ene, were synthesized by the metathesis of cardanol with symmetrical internal alkenes. These derivatives were methoxycarbonylated to produce monomers with different chain lengths such as methyl‐16‐(3‐hydroxyphenyl)hexadecanoate; HOPhC15COOMe, methyl‐13‐(3‐hydroxyphenyl)tridecanoate; HOPhC12COOMe, methyl‐12‐(3‐hydroxyphenyl)dodecanoate; HOPhC11COOMe, methyl‐11‐(3‐hydroxyphenyl)undecanoate; HOPhC10COOMe, and methyl‐10‐(3‐hydroxyphenyl)decanoate; HOPhC9COOMe, respectively. Polymerization of the synthesized monomers produced oligomers that consist of up to seven monomer units as confirmed by MALDI‐TOF‐MS. Lactone formation was also observed in some cases under polymerization conditions.