Yonemitsu modification

The stereocontrolled total synthesis of (-)-macrolactin A, a 24-membered macrolide, was achieved by J.P. Marino and co-workers/ The key macrocyclization step was carried out using the Yonemitsu modification of the Yamaguchi macroiactonization. In this procedure, the mixed anhydride is added to the highly dilute solution of DMAP rapidly (in one portion) at room temperature. The final step of the total synthesis was the removal of the protecting groups under acidic condition. 

Nishida. A.. Yagi, K., Kawahara, N., Nishida, M., and Yonemitsu, ()., Chemical modification of erythromycin A. Synthesis of the C1-C9 fragment from erythromycin A and reconstruction of the macrolactone ring. Tetrahedron Lett., 36, 3215, 1995. 

The original Yonemitsn reaction is fonnd relatively rare in contemporary literatnre, but many modifications by exchange of the CH-acidic or the heterocyclic component have been pnblished. These modifications make the Yonemitsn reaction a broadly applied MCR in organic synthesis, thongh their classification being a modification of the Yonemitsu reaction is not always mentioned in the literatnre. 

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