488-06-2Relevant articles and documents
-
Nishikawa et al.
, p. 2723 (1969)
-
-
Nishikawa,Hirata
, p. 2591,2592 (1967)
-
Stereodivergent Synthesis of 1-Hydroxymethylpyrrolizidine Alkaloids
Appayee, Chandrakumar,Sarkale, Abhijeet M.
, (2020/06/05)
A first stereodivergent strategy for the asymmetric synthesis of all stereoisomers of 1-hydroxymethylpyrrolizidine alkaloids is developed using an asymmetric self-Mannich reaction as a key step. An anti-selective self-Mannich reaction of methyl 4-oxobutanoate with the PMP-amine catalyzed by a chiral secondary amine is successfully optimized for the asymmetric synthesis of (+)-isoretronecanol and (-)-isoretronecanol. A syn-selective self-Mannich reaction catalyzed by proline is utilized for the asymmetric synthesis of the diastereomer, (+)-laburnine, and its enantiomer, (-)-trachelanthamidine.
The stereoselective addition of titanium(IV) enolates of 1,3-oxazolidin-2-one and 1,3-thiazolidine-2-thione to cyclic N-acyliminium ion. The total synthesis of (+)-isoretronecanol
Pereira, Elaine,De Fátima Alves, Concei??o,B?ckelmann, Maria Alice,Pilli, Ronaldo A.
, p. 2691 - 2693 (2007/10/03)
(+)-Isoretronecanol (1) has been prepared in four steps and 36% overall yield via the diastereoselective addition of the titanium(IV) enolate derived from N-4-chlorobutyryl-1,3-thiazolidine-2-thione (3) to N-Boc-2- methoxypyrrolidine (5), which afforded 2-substituted pyrrolidine 7 in 84% yield (8:1 diastereoisomeric ratio), followed by reductive recovery of the chiral auxiliary and cyclization.