The RuCl3 catalyzed reaction of β-lactams in the presence of acetaldehyde and molecularoxygen in an acid and ethyl acetate under buffer conditions gives the corresponding 4-acyloxy β-lactams highly efficiently.
The conversion of β-amino esters by alkylaluminum compounds into β-lactams
作者:Helmut Vorbrüggen、Robert Burns Woodward
DOI:10.1016/s0040-4020(01)80350-1
日期:——
β-Amino esters with an unsubstituted amino group such as 1 or 19 can be cyclized by two equivalents of alkylaluminum compounds such as triisobutylaluminum in yields up to 61% to the corresponding β-lactams 2 or 20.
Nitrosative deamination of 1-aminoazetidin-2-ones. An entry to N-unsubstituted β-lactams
作者:James D. White、Steven T. Perri、Steven G. Toske
DOI:10.1016/s0040-4039(00)93960-1
日期:1992.1
Nitrosative deamination of 1-aminoazetidin-2-ones was carried out with diphenylnitrosamine to give the N-unsubstituted systems, thus completing a route to β-lactams by photochemical ringcontraction of pyrazolidin-3 ones.
Hydrolyticdeallylation of N-allyl amides to give amides and propanal can be achieved with PdII catalysts. The optimized catalyst consists of Pd(OCOCF3)2 and 1,3-bis(diphenylphosphanyl)propane (DPPP). Several kinds of open-chain N-allyl amides and N-allyl lactams undergo hydrolyticdeallylation to give the corresponding amides and lactams in good to high yield. A mechanism which includes isomerization
through the use of readily accessible alkenyl dioxazolone derivatives. The reaction transcends the conventional NiH operation mode via a transposed mechanism initiated by N-activation, thus allowing for proximal C–N bond formation with excellent regioselectivity, regardless of the electronic properties of substituents. This mechanistic platform is also highly effective for the enantioselective intramolecular