Addition Reaction of Carboxylic Anhydrides to the Carbon-Nitrogen Double Bond of Unsubstituted Cyclic Imidates
作者:Shiro Kobayashi、Michihisa Isobe、Takeo Saegusa
DOI:10.1246/bcsj.55.1921
日期:1982.6
cyclic (SAn and GAn) carboxylic anhydrides were added at room temperature to the C=N bond of unsubstituted cyclic imidates of 2-oxazoline (OZO) and 5,6-dihydro-4H-1,3-oxazine (OZI) to give addition products quantitatively. In contrast to these findings, the reactions of acetyl halides with OZO and OZI yielded ringopened products and the reactions of carboxylic anhydrides with 2-benzyl-2-oxazoline (BzOZO)
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
Photolytic reaction of chromium and molybdenum carbene complexes with imines
作者:Louis S. Hegedus、Lisa M. Schultze、Jose Toro、Chen Yijun
DOI:10.1016/s0040-4020(01)91422-x
日期:1985.1
β-lactams, including a cepham analog, were synthesized by the photochemical reaction of [(methoxy)(methyl)carbene]chromiumcomplexes with substituted imines. Oxazines and oxazolines were inert towards chromiumcarbenecomplexes. Oxazines were converted to bicyclic β-lactams by the photolyticreaction of molybdenum carbenecomplexes. Oxazolines were considerably less reactive and produced only low yields
Polyamines mimicking substances which occur naturally in biosilicas have been synthesized and show an accelerating effect on silica condensation, which depends on the chemical nature, the architecture (linear or branched), and the degree of polymerization.
A contribution to the confusion surrounding the reaction of ketenes with imines to produce .beta.-lactams. A comparison of stereoselectivity dependence on the method of ketene generation: acid chloride/triethylamine vs photolysis of chromium carbene complexes
作者:Louis S. Hegedus、John Montgomery、Yukitoshi Narukawa、Daniel C. Snustad
DOI:10.1021/ja00015a036
日期:1991.7
The stereoselectivity of the reaction of imines of benzaldehyde and cinnamaldehyde with ketenes generated by the reaction of optically active oxazolidinone acid chlorides with triethylamine and complexed ketenes generated by photolysis of optically active oxazolidine ― and oxazolidinone-chromium-carbene complexes in the presence and absence of added triethylamine was compared. The absolute stereochemistry