180324-13-4Relevant articles and documents
Conjugate addition of 6-membered hydrazine to chiral tert-butyl (E)-2-(p-tolylsulfinyl)cinnamates. Synthesis of (S)-celacinnine
Matsuyama,Itoh,Matsumoto,Ohira,Hara,Yoshida,Iyoda
, p. 2924 - 2930 (2007/10/03)
Two enantiomers of the bicyclic lactam, (S)- and (R)-9-phenyl-1,6-diazabicyclo[4.3.0]nonan-7-one (6), were synthesized stereoselectively with high optical purity (95% ee) by the asymmetric conjugate addition-cyclization of piperidazine to chiral vinyl sulfoxides, tert-butyl (E)-2-[(R)- and (S)-p-tolylsulfinyl]cinnamate (4), followed by removal of the p-tolylsulfinyl group with SmI2. The subsequent reductive cleavage of the N-N bond of the bicyclic lactam 6 with sodium in liquid ammonia produced the corresponding 9-membered azalactam, (S)- and (R)-4-phenyl-1,5-diazacyclononan-2-one (7) with 99% and 97% ee, respectively. X-ray crystallography showed that (S)-7 exists exclusively as a trans conformer in the crystal state. Starting from (S)-7, naturally occurring (S)-celacinnine 1 was synthesized with 99% ee employing the ring-expansion reaction via intramolecular transamidation.
95. Asymmetric synthesis of the alkaloids mayfoline and N(1)-Acetyl-N(1)-deoxymayfoline
Kuehne, Paul,Linden, Anthony,Hesse, Manfred
, p. 1085 - 1094 (2007/10/03)
The total syntheses of the spermidine alkaloids (-)-mayfoline (11) and (+)-N(1)-acetyl-N(1)-deoxymayfoline (12) are described. These macrocyclic lactams belong to the most interesting conjugates of the polyamine derivatives very commonly found in nature. The enantioselective syntheses were achieved through resolution of the methyl 3-amino-3-phenylpropanoate (2) by recrystallization of its (+)-L-tartrate salt. Construction of the 13-membered ring ensued through condensation, reductive ring expansion (internal bond cleavage), and finally a transamidation reaction involving a second ring expansion.