Reagents and synthetic methods. Part 67. Preparation of 4-unsubstituted .beta.-lactams from 4-acetoxyazetidin-2-ones. A formal approach to monobactams and nocardicins
A Cation-exchange Resin Promoted Imino Aldol Reaction, Leading to the Synthesis of 2-Isocephem and 2-Oxa-isocephem
作者:Makoto Shimizu、Masanori Tachi、Iwao Hachiya
DOI:10.1246/cl.2004.1394
日期:2004.10
Imino aldol reaction of ketene silyl acetals with the chiral imine 1 proceeds smoothly to giveβ-amino esters in good yields with high diasetereoselectivity under the influence of a cation-exchange resin, and the subsequent functional group transformations provide a formal synthesis of 2-isocephem and 2-oxa-isocephem β-lactam antibiotics.
A concise synthesis of 4-unsubstituted azetidin-2-ones
作者:Fernando P. Cossío、Begoña Lecea、Claudio Palomo
DOI:10.1039/c39870001743
日期:——
On catalysis by trimethylsilyl trifluoromethanesulphonate, 4-acetoxy-β-lactams react with hydrosilanes to give 4-unsubstituted-β-lactams in good to excellent yields.
Reagents and synthetic methods. Part 67. Preparation of 4-unsubstituted .beta.-lactams from 4-acetoxyazetidin-2-ones. A formal approach to monobactams and nocardicins
作者:Ana Arrieta、Begona Lecea、Fernando P. Cossio、Claudio Palomo