TRANS-3,5-DISUBSTITUTEDPYRROLIDINE: ORGANOCATALYST FOR anti-MANNICH REACTIONS
申请人:Tanaka Fujie
公开号:US20070117986A1
公开(公告)日:2007-05-24
A compound of Formula I is disclosed, in which R is a substituent containing a hydrogen bond-forming atom within three atoms from the ring carbon to which the substituent is bonded; X is CH
2
, O, S or NR
1
, wherein R
1
is a hydrocarbyl group or an amino-protecting group having one to about 18 carbon atoms; R
2
is hydrido or a hydrocarbyl group containing one to about twelve carbon atoms; and R
3
is hydrido or methyl, but both R
2
and R
3
are not hydrido when X is CH
2
A molecule of Formula I and those in which R
2
and R
3
can both be hydrido (Formula X) functions as a catalyst in a Mannich reaction to asymmetrically form β-aminoaldehyde or β-aminoketone diastereomeric products having two chiral centers on adjacent carbon atoms and in which the anti-diastereomers are in excess over the syn-diastereomers. Methods for carrying out those syntheses are also disclosed.
Entirely Solvent-Free Procedure for the Synthesis of Distillable 1,3-Dithianes Using Lithium Tetrafluoroborate as a Reusable Catalyst
作者:Tsuneo Sato、Kiyoshi Kazahaya、Shinya Tsuji
DOI:10.1055/s-2004-829084
日期:——
Treatment of various types of aldehydes and ketones with 1,3-propanedithiol in the presence of a catalytic amount of lithium tetrafluoroborate at 25 °C under solvent-free conditions followed by direct purification by distillation of the resulting mixture affords the corresponding 1,3-dithianes in good to excellent yields. Chemoselective protection of keto aldehydes is also successfully achieved over the catalyst. The catalyst can be recovered and reused.
Tandem Carbon−Carbon Bond Constructions via Catalyzed Cyanation/Brook Rearrangement/C-Acylation Reactions of Acylsilanes
作者:Xin Linghu、David A. Nicewicz、Jeffrey S. Johnson
DOI:10.1021/ol0263649
日期:2002.8.1
see text] A tandem nucleophile-catalyzed cyanation/Brookrearrangement/C-acylation has been developed. Phase transfer cocatalysts facilitate cyanide-catalyzed reactions between acylsilanes and cyanoformates to afford protected tertiary carbinol products. A catalytic cycle is proposed involving cyanation of an acylsilane, [1,2]-Brook rearrangement, and C-acylation of the derived carbanion by a cyanoformate
[EN] TECHNOLOGIES USEFUL FOR OLIGONUCLEOTIDE PREPARATION<br/>[FR] TECHNOLOGIES UTILES POUR LA PRÉPARATION D'OLIGONUCLÉOTIDES
申请人:WAVE LIFE SCIENCES LTD
公开号:WO2020191252A1
公开(公告)日:2020-09-24
Among other things, the present disclosure provides technologies for oligonucleotide preparation, particularly chirally controlled oligonucleotide preparation, which technologies provide greatly improved crude purity and yield, and significantly reduce manufacturing costs.
Chemoselective (Trans)thioacetalization of Carbonyl Compounds with a Reusable Lewis Acid-Surfactant-Combined Copper Bis(dodecyl sulfate) Catalyst in Water
A Lewis acid-surfactant-combined copper bis(dodecyl sulfate) [Cu(DS)2] catalyst served as an efficient and reusable catalyst for the thioacetalization and transthioacetalization of carbonyl compounds and O,O-acetals in water at room temperature. Some of the major advantages of this procedure are high chemoselectivity, ease of operation and purification without any organic solvent, and high yields.