22650-19-7Relevant academic research and scientific papers
Further studies of intramolecular michael reactions of nitrosoalkenes for construction of functionalized bridged ring systems
Kumar, Praveen,Li, Puhui,Korboukh, Ilia,Wang, Tony L.,Yennawar, Hemant,Weinreb, Steven M.
body text, p. 2094 - 2101 (2011/06/17)
A wide variety of stabilized carbanions have been found to participate as nucleophiles in intramolecular Michael-type conjugate additions to in situ generated nitrosoalkenes to form bridged carbocyclic systems. The vinylnitroso platforms for these cyclizations have been prepared via two key steps involving ring-closing metathesis of vinyl chlorides and regioselective conversion of vinyl chlorides to α-chloroketones with sodium hypochlorite in glacial acetic acid/acetone. An alternative approach to preparation of some cyclization substrates has involved use of more reactive enol ethers as precursors to the requisite α-chloroketones. A sulfonamide anion has also been found to be an effective nucleophile in this type of reaction, leading to formation of a 6-azabicyclo[3.2.1]octane.
EINE NEUE SYNTHESE VON VINBLASTIN-DERIVATEN IV . SYNTHESE VON 20'-DEETHYL-20'-DEOXYVINBLASTIN und 20'-DEETHYL-20'-DEOXYVINCOVALIN UEBER 3,Nb-SECO-CLEAVAMIN-DERIVATIVE ALS ZWISCHENSTUFEN
Schill, Gottfried,Priester, Claus Ulrich,Windhoevel, Udo Frank,Fritz, Hans
, p. 3765 - 3786 (2007/10/02)
Coupling of racemic 16-methoxycarbonyl-15,20-dihydro-3,Nb-seco-cleavamine derivative 34 with (-)vindoline via chloroindolenine intermediate 41 occurs with high stereoselectivity and leads after cyclization to the separable dimers 46I and 46II with natural C(14'), C(16')-configuration in good yields.Tetracyclic lactam 37 with vinblastine analogous stereochemistry is prepared and transfomed to chloroindolenine 38.Coupling of 38 with N,N-dimethyl-m-anisidine was achieved in good yield.
