A versatile, synthesis of β-amino acids using the Nicholas reaction. I. Application to β-lactams of the carbapenem class
作者:Peter A. Jacobi、Wanjun Zheng
DOI:10.1016/s0040-4039(00)77630-1
日期:1993.4
Homochiral acetylenic acids of general structure 10, prepared using the Schreiber modification of the Nicholas reaction, have been converted to β-amino acid derivatives of type 11 by a two steps sequence involving Curtius rearrangement followed by oxidative cleavage of the acetylenic bond. Amino acid derivatives 11 are excellent precursors for β-lactams of the carbapenem class.
Formal Total Syntheses of the β-Lactam Antibiotics Thienamycin and PS-5
作者:Peter A. Jacobi、Shaun Murphree、Frederic Rupprecht、Wanjun Zheng
DOI:10.1021/jo952092u
日期:1996.1.1
Chiral nonracemic acetylenic acids of general structure 11, prepared using the Schreiber modification of the Nicholas reaction, have been converted to beta-amino acid derivatives of type 12 by a two-step sequence involving Curtius rearrangement followed by oxidative cleavage of the acetylenic bond. Amino acid derivatives 12 are excellent precursors for beta-lactams of the carbapenem class, including the important antibiotics thienamycin (1) and PS-5 (4).
Dihydropyrromethenones by Pd(0)-Mediated Coupling of Iodopyrroles and Acetylenic Amides. Synthesis of the A,B-Ring Segment of Phytochrome
作者:Peter A. Jacobi、Jiasheng Guo、S. Rajeswari、Wanjun Zheng
DOI:10.1021/jo970289b
日期:1997.5.1
Dihydropyrromethenone derivative 32b, which constitutes the A,B-ring segment of phytochrome (6), has been prepared in enantiomerically pure form beginning with acetylenic amide 47b and iodopyrrole 27. The key steps involved the TBAF-catalyzed 5-exo-dig cyclization of the acetylenic pyrrole 48b, followed by thia-Mitsunobu inversion of the resulting alcohol derivative 31b.