137169-33-6Relevant articles and documents
Stereodivergence in the Ireland-Claisen Rearrangement of α-Alkoxy Esters
Podunavac, Ma?a,Lacharity, Jacob J.,Jones, Kerry E.,Zakarian, Armen
supporting information, p. 4867 - 4870 (2018/08/24)
A systematic investigation into the Ireland-Claisen rearrangement of α-alkoxy esters is reported. In all cases, the use of KN(SiMe3)2 in toluene gave rearrangement products corresponding to a Z-enolate intermediate with excellent diastereoselectivity, presumably because of chelation control. On the other hand, chelation-controlled enolate formation could be overcome for most substrates through the use of lithium diisopropylamide (LDA) in tetrahydrofuran (THF).
An inexpensive carbohydrate derivative used as a chiral auxiliary in the synthesis of α-hydroxy carboxylic acids
Yu, Hongwu,Ballard, C.Eric,Boyle, Paul D,Wang, Binghe
, p. 7663 - 7679 (2007/10/03)
Protected α-hydroxy carboxylic acids were synthesized in moderate yield and high diastereoselectivity by alkylation of glycolate (α-hydroxy acetate) enolates using a D-fructose-derived chiral auxiliary. The new chiral center was assigned the R configuration based on comparisons of optical rotations and on one crystal structure analysis. This alkylation methodology is compatible with several hydroxyl protecting groups. The free hydroxy acids were obtained upon removal of the protecting group from the hydroxyl functionality followed by saponification.
Short synthesis of the optically active E-ring portion of (S)-camptothecin
Leue,Miao,Kanazawa,Genisson,Garcon,Greene
, p. 2903 - 2905 (2007/10/03)
The short synthesis of the optically active E-ring portion of (S)-camptothecin was presented. (5S)-5-Benzyloxy-5-ethyl-6-oxo-5,6-dihydro-2H-pyran-3-carboxylic acid, the protected E-ring moiety of (S)-camptothecin, were rapidly prepared in enantiomerically
