AsymmetricvinylogousMannichreaction (VMR) of 2-(tert-butyldimethylsilyloxy)furan (TBSOF, 1) with (RS)- or (SS)-t-BS-imines (3) furnished 5-aminoalkylbutenolides 7a–k in 75–87% yields with anti/syn ratios ranging from 75:25 to 97:3. Butenolides 7a–f,k were readily converted into substituted lactones 8 and 5 and 6-substituted 5-hydroxypiperidin-2-ones 11a–g, which are, in turn, key intermediates for
Efficient synthesis of Xaa-Gly type (Z)-chloroalkene dipeptide isosteres via organocuprate mediated reduction
作者:Takuya Kobayakawa、Hirokazu Tamamura
DOI:10.1016/j.tet.2016.06.080
日期:2016.8
A highly stereoselective synthesis of (Z)-chloroalkene dipeptideisosteres (CADIs) of the Xaa-Gly type has been achieved. Treatment of an allylic gem-dichloride with an organocuprate provided (Z)-chloroalkene formation corresponding to an Xaa-Gly type CADI through reductive dechlorination in high yield with (Z)-selectivity.
Synthesis of chiral β2,2,3-3-amino-2-hydroxyalkanoates and 3-alkyl-3-hydroxy-β-lactams by double asymmetric induction
作者:Andrea Guerrini、Greta Varchi、Rizzo Daniele、Cristian Samorì、Arturo Battaglia
DOI:10.1016/j.tet.2007.05.069
日期:2007.8
Reactions of chiral (2S)-enolates of dioxolan-4-ones, derived from lactic, mandelic, and phenyllactic acids, with aliphatic (SS)- and (SR)-tert-butylsulfinyl aldimines afforded conformationally restrained C2-disubstituted N,O-orthogonally protected 3-amino-2-hydroxyalkanoates in the form of N-sulfinyl protected 1′-aminodioxolan-4-ones. The product distribution showed that there is significant kinetic
Desymmetrization of Metallated Cyclohexadienes with Chiral <i>N-tert</i>-Butanesulfinyl Imines
作者:Modhu Sudan Maji、Roland Fröhlich、Armido Studer
DOI:10.1021/ol800478q
日期:2008.5.1
This communication describes the desymmetrization of various achiral metallated cyclohexadienes with a series of chiral N-tert-butanesulfinyl imines. Depending on the metal used, either the symmetrical diene (dicyclohexadienyl-zinc) or the desymmetrized diene (cyclohexadienyl-MgCl) is obtained in a good regioselectivity with excellent diastereoselectivity. The products formed should be useful building blocks for natural product synthesis. The symmetrical 1,4-dienes are readily oxidized to the corresponding diarylmethylamine derivatives.
VERWENDUNG VON PRÄKURSOREN FÜR DIE HERSTELLUNG VON KOHLENSTOFF-11-MARKIERTEN AMINOSÄUREN UND DERIVATEN DAVON