Abstract: Even to this day, very few reactions can compete with the Pauson-Khand reaction(PKR) when it comes to introducing great complexity in a single step of synthesis. The process yields cyclopentenones, easily converted to cyclopentanones, a structure very common in natural products. First reported in the seventies1, originally the main drawback of PKR used to be its poor scope and lack of significant yields. But now a days there are various successful methodologies available like using BINAP2, derivatives of BINOL3 or even metals other than cobalt4 to make this reaction of routine use during complex synthesis, especially of polycyclic molecules. Furthermore, asymmetry can also be introduced in moderate to good yields using different strategies ranging from strategically synthesised bidentate ligands5,6 to using chiral auxiliaries like Oppolzer’s camphorsultam7 or chiral promoters like amine N-oxides8 derived from natural alkaloids, turning it into a powerful tool for natural product synthesis of α- and β-cedrenes9, Asteriscanolide10 and (+) Fusarisetin A11
References:
- U. Khand , G. R. Knox , P. L. Pauson , W. E. Watts and M. I. Foreman , J. Chem. Soc., Perkin Trans. 1, 1973, 977 -981
- Hiroi , T. Watanabe , R. Kawagishi and I. Abe , Tetrahedron: Asymmetry, 2000, 11, 797
- J. Sturla and S. L. Buchwald , J. Org. Chem., 2002, 67, 3398
- M. Brummond , M. M. Davis and C. Huang , J. Org. Chem., 2009, 74 , 8314 -8320
- Orgue S, Leon T, Riera A, Verdaguer X. Org Lett. 2015; 17,250–253
- Cristobal-Lecina E, Costantino AR, Grabulosa A, Riera A, Verdaguer X. Organometallics. 2015; 34,4989–4993.
- Marchueta , E. Montenegro , D. Panov , M. Poch , X. Verdaguer , A. Moyano , M. A. Pericàs and A. Riera , J. Org. Chem., 2001, 66, 6400
- R. Carbery , W. J. Kerr , D. M. Lindsay , J. S. Scott and S. P. Watson , Tetrahedron Lett., 2000, 41, 3235
- J. Kerr , M. McLaughlin , A. J. Morrison and P. L. Pauson , Org. Lett., 2001, 3, 2945
- M. E. Krafft , Y. Y. Cheung and K. A. Abboud , J. Org. Chem., 2001, 66 , 7443
- Jun Huang, Lichao Fang, Rong Long, Li-Li Shi, Hong-Juan Shen, Chuang-chuang Li, and Zhen Yang Organic Letters 2013 15 (15), 4018-4021\