148968-87-0Relevant academic research and scientific papers
High diastereoselective vinylogous Mannich reaction induced by O-pivaloylated d-galactosylamine as the chiral auxiliary: Stereoselective synthesis of 8-arylazocan-2-one
Cui, Bing,Hou, Gang,Cai, Yan,Miao, Zhiwei
, p. 1 - 7 (2013/06/27)
The diastereospecific formation of β-N-glycosidically linked α,β-unsaturated δ-amino aldehyde derivatives has been achieved with high yield via a vinylogous Mannich reaction. The reaction was performed by using a O-pivaloylated galactosyl amine as a chiral template and AlCl 3 as a promoter in THF. (S)-8-(p-Nitrophenyl) azocan-2-one can be stereoselective synthesized from (S) ethyl 7-galactosylamino-7-(p-nitrophenyl) hepta-2,4-dienoate by sequential hydrogenation of the double bond, cyclic lactam formation, and removal of the N-glycosidic auxiliary under basic conditions.
Lewis acid catalyzed diastereoselective vinylogous Mannich reaction induced by O-pivaloylated d-galactosylamine as the chiral auxiliary: Stereoselective synthesis of 6-arylpiperidin-2-ones
Cui, Bing,Kong, Shasha,Wu, Guiping,Miao, Zhiwei,Chen, Ruyu
supporting information; experimental part, p. 111 - 119 (2012/03/26)
The diastereospecific formation of β-N-glycosidically linked α,β-unsaturated δ-aminocarbonyl derivatives, in the form of (S)-δ-amino-δ-arylpent-2-enoic ester, has been achieved in high yield via a vinylogous Mannich reaction, utilizing poly-O-pivaloylated
Stereoselective synthesis of α-amino(phenyl)methyl(phenyl)phosphinic acids with O-pivaloylated D-galactoslamine as chiral auxiliary
Wang, Yadan,Wang, Yangyun,Yu, Jipan,Miao, Zhiwei,Chen, Ruyu
supporting information; experimental part, p. 9290 - 9293 (2010/04/05)
Stereoselective synthesis of α-amino (phenyl)methyl(phenyl)phosphinic acids with O-pivaloylated D-galactosylamine as chiral auxiliary, was reported. 2 3 drops of acetic acid were added to a solution of amine 1 and aldehyde 2 in 2-propanol and the mixture was stirred at room temperature for about 0.5 h. A solution of N-galactosylaldimines 3 in THF was cooled to 0°C, and phosphinate 4 and SnCl4 were added. The mixture was stirred for 2 d at room temperature. The aqueous phase was extracted with CHCl3 and the organic layers were dried with anhydrous MgSO4, filtered, and concentrated in vacuo to yield the crude products. A solution of compound 5 in dry methanol was treated with freshly prepared solution of HCl. Then methanol was evaporated in vacuo and the remaining residue dissolved in 0.5 M HCl and extracted with pentane. The results revealed that AlCl3, SnCl 4, and BF3.OEt2 were able to promote the addition.
Practical stereo- and regioselective, copper(I)-promoted Strecker synthesis of sugar-modified α,β-unsaturated imines
Zhou, Guobin,Zheng, Weixin,Wang, Dong,Zhang, Pengfei,Pan, Yuanjiang
, p. 520 - 526 (2007/10/03)
The regio- and stereoselective, Lewis acid catalyzed Strecker reaction between Me3SiCN and different aldimines incorporating a 2,3.4,6-tetrakis-O-pivaloyl-D-glucopyranosyl (Piv4Glc) chiral auxiliary has been worked out. Depending on
A novel reductive aminocyclization for the syntheses of chiral pyrrolidines: Stereoselective syntheses of (S)-nornicotine and 2-(2'-pyrrolidyl)-pyridines
Loh, Teck-Peng,Zhou, Jian-Rong,Li, Xu-Ran,Sim, Keng-Yeow
, p. 7847 - 7850 (2007/10/03)
(S)-Nornicotine 2 was synthesized in four steps. A key step in the synthesis involved reductive aminocyclization of a 1,4-ketoaldehyde with 2,3,4,6-tetra-O-pivaloyl-β-D-galactosylamine 1 in the presence of sodium cyanoborohydride, diastereoselectively affording the corresponding stereoisomer 6 in 45% yield. The aminosugar moiety could be easily removed by acidic hydrolysis to furnish 2. The aminocyclization was further extended to asymmetric syntheses of novel chiral 2-(2'-pyrrolidyl)-pyridine ligands 12 and 13.
Carbohydrates as Chiral Templates: Diastereoselective Synthesis of N-Glycosyl-N-homoallylamines and and β-Amino Acids from Imines
Laschat, Sabine,Kunz, Horst
, p. 5883 - 5889 (2007/10/02)
Complexing properties and chirality of carbohydrates were utilized in diastereoselective reactions of O-pivaloylated N-galactosylimines with allylsilanes and -stannanes.With allyltrimethylsilane in the presence of SnCl4 imines 2 of aromatic and heteroaromatic aldehydes were converted to homoallylamines 3, giving ratios of diastereomers higher than 7:1.No addition products derived from α-anomeric aromatic imines were formed.Aliphatic homoallylamines 3 were synthesized by using allyltributylatannane in the presence of SnCl4.Both α- and β-anomeric aliphatic imines reacted with the allylstannane.They gave the same ratio of diastereomers and showed the same sense of asymmetric induction.
Hetero-Diels-Alder Reactions on a Carbohydrate Template: Stereoselective Synthesis of (S)-Anabasin
Pfrengle, Waldemar,Kunz, Horst
, p. 4261 - 4263 (2007/10/02)
Diastereoselective aza-Diels-Alder reaction using the tetra-O-pivaloyl-β-D-galactopyranosylamine as the chiral template affords the synthesis of enantiomerically pure 2-substituted piperidine derivatives, e.g. the tobacco alkaloid (S)-anabasin.
CARBOHYDRATES AS CHIRAL TEMPLATES: ASYMMETRIC UGI-SYNTHESIS OF ALPHA-AMINO ACIDS USING GALACTOSYLAMINES AS THE CHIRAL MATRICES
Kunz, Horst,Pfrengle, Waldemar
, p. 5487 - 5494 (2007/10/02)
In the presence of Lewis acid catalysts O-acetyl- (1) and O-pivaloyl- (2) protected β-D-galactopyranosylamines react with aldehydes, isocyanides and carboxylic acids in Ugi-four-component-condensations to give the corresponding N-galactosyl-amino acid amide derivatives 3, 5 in almost quantitative yields.Zinc chloride is the most effective Lewis acid catalyst.At 0 deg C or even at room temperature the (2R,β-D)-diastereomers of the amino acid derivatives 3, 5 are formed with high diastereoselectivity.If the sterically more demanding O-pivaloyl galactosylamine 2 is used at -78 deg C to -25 deg C the stereoselectivity often exeeds 20:1 favouring the (2R,β-D) diastereomers 5.After one recrystallisation pure (R)-amino acid derivatives 5 are obtained in yields of 80-95percent.In addition to the high yields and stereoselectivity the amino acid synthesis described here has the further advantage that it neither requires organometallic reagents and intermediates nor exclusion of oxygen and moisture.Two step acid hydrolysis of the N-galactosylamino acid amide derivatives 5 delivers the enantiomerically pure (R)-amino-acids 8 in high yields.
