Highly Chemoselective Trichloroacetimidate-Mediated Alkylation of Ascomycin: A Convergent, Practical Synthesis of the Immunosuppressant L-733,725

…, EG Corley, AS Thompson, J McNamara…

Index: Song, Zhiguo; DeMarco, Anthony; Zhao, Mangzhu; Corley, Edward G.; Thompson, Andrew S.; McNamara, James; Li, Yulan; Rieger, Dale; Sohar, Paul; Mathre, David J.; Tschaen, David M.; Reamer, Robert A.; Huntington, Martha F.; Ho, Guo-Jie; Tsay, Fuh-Rong; Emerson, Khateeta; Shuman, Richard; Grabowski, Edward J. J.; Reider, Paul J. Journal of Organic Chemistry, 1999 , vol. 64, # 6 p. 1859 - 1867

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Citation Number: 11

Abstract

L-733,725, a new immunosuppressant drug candidate, was prepared by a highly chemoselective alkylation of the macrolide ascomycin at the C32 hydroxy position with the imidazolyl trichloroacetimidate 16. The trichloroacetimidate-activated side chain 16 was prepared by an efficient four-step sequence in 42% overall yield. The high chemoselectivity in the alkylation of the C32 hydroxy group of the unprotected ascomycin was the result of ...