Synthesis of optically active .beta.-lactams by the photolytic reaction of imines with optically active chromium carbene complexes
作者:Louis S. Hegedus、Rene Imwinkelried、Marie Alarid-Sargent、Dalimil Dvorak、Yoshitaka Satoh
DOI:10.1021/ja00159a034
日期:1990.1
Opticallyactivechromium carbene complexes utilizing (S)-valine- and (R)-phenylglycine-derived chiral auxillaries were synthesized and subjected to photolytic reaction with a number of imines. Opticallyactive β-lactams were produced in good to excellent chemical yield and with high diastereoisomeric excess. Procedures for removal of the chiral auxilliary to produce the opticallyactive free amino
Chiral auxiliary control of tacticity in free radical polymerization
作者:Ned A. Porter、Timothy R. Allen、Robert A. Breyer
DOI:10.1021/ja00046a011
日期:1992.9
Chiral oxazolidine acrylamides undergo stereocontrolled free radicalpolymerization. Remarkably high degrees of tacticity have been demonstrated in the polymerization of acrylamides with these chiral auxiliaries that are derived from valine, phenylglycine, and tert-leucine. The polyacrylamides formed in these polymerizations can be converted to poly(acrylic acid), P(AA), and poly(methyl acrylate),
Penultimate group effects in free radical telomerizations of acrylamides
作者:Ned A. Porter、Randall L. Carter、Christopher L. Mero、Michael G. Roepel、Dennis P. Curran
DOI:10.1016/0040-4020(96)00077-4
日期:1996.3
The telomerizaton of several acrylamides, most containing chiral auxiliary groups, was investigated. The first-formed stereogenic center in the n=2 telomer (the penultimate center) has a significant effect on the configuration of the second (ultimate) center in the product. The penultimate chiral center of oxazolidine-derived acrylamides directs the configuration of the ultimate center such that the
Diastereoselective Reactions of the Tiglic Acid Functionality Mediated by Oxazolidine Chiral Auxiliaries: A Mechanistic Comparison of DMD andm-CPBA Epoxidations versus Singlet Oxygen and PTAD Ene Reactions
作者:Aurelia Pastor、Waldemar Adam、Thomas Wirth、Gábor Tóth
Asymmetric 1,2‐Carbamoyl Rearrangement of Lithiated Chiral Oxazolidine Carbamates and Diastereoselective Synthesis of α‐Hydroxy Amides
作者:Arun K. Ghosh、Amartyo J. Basu、Che‐Sheng Hsu、Monika Yadav
DOI:10.1002/chem.202200941
日期:2022.8
Asymmetric 1,2-carbamoyl rearrangement of chiral 2-alkenyl oxazolidine carbamates were investigated. These rearrangements provided α-hydroxy amide derivatives with excellent diastereoselectivity and in good to excellent isolated yields. The substrate scope of the reaction was examined with a variety of 2-alkenyl and benzyl oxazolidine carbamates. The observed high degree of diastereoselectivity was