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.
Synthesis of chiral hexynones for use as precursors to native photosynthetic hydroporphyrins
作者:Khiem Chau Nguyen、Duy T. M. Chung、Phattananawee Nalaoh、Jonathan S. Lindsey
DOI:10.1039/d3nj03900e
日期:——
by derivatization of the chiral Weinreb pentynamide. Third, one (semisynthetic) chiral hexynone bearing a native phytyl substituent, a near-universal precursor to ring D of photosynthetic hydroporphyrins, was prepared in 2.5 mmol quantity. The synthesis and manipulation were achieved while maintaining stereochemical integrity in these somewhat densely functionalized chiral hexynones (three functional
光合四吡咯大环化合物的计划全合成通过已建立的不对称方法在早期前体中安装了必要的立体化学特征。关键构建模块是含有手性吡咯啉单元的二氢二吡啶,手性六-5-yn-2-酮是其有价值的前体。寻找在 1 位带有不同官能团的手性 hex-5-yn-2-one,其对应于细菌叶绿素 a 的手性吡咯啉单元(环 B 和 D )。本文报告了三个主要结果。首先,将通过Schreiber 改进的尼古拉斯反应制备的 (2 R ,3 R )-3-乙基-2-甲基戊-4-炔酸转化为类似的手性 Weinreb 戊酰胺。后者用三丁基锡-一碳合成子处理,产生 1-羟基己基-5-yn-2-酮支架,其中包含两个必需的立体中心,并具有新引入的游离形式或保护为 Me、MOM、THP 的羟基。 、MEM、Bn 或 SEM 导数。其次,在获得前 B 化合物 (3 R ,4 R )-1,1-二甲氧基-3-乙基-4-甲基己-5-yn-2-one
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).