Sulfur derivatives of ephedra alkaloids; new and highly efficient chiral catalysts.

Synthesis of N-Alkylated and N-Arylated Derivatives of 2-Amino-2‘-hydroxy-1,1‘-binaphthyl (NOBIN) and 2,2‘-Diamino-1,1‘-binaphthyl and Their Application in the Enantioselective Addition of Diethylzinc to Aromatic Aldehydes

“…Following the pioneering work of Oguni and Omi, numerous chiral amino alcohols have been surveyed as ligands in the R 2 Zn addition to aldehydes and some spectacular enantioselectivities have been reported (90−99% ee), ,,− especially with DAIB 21,22 and DBNE. , However, inspection of the impressively long list of these ligands reveals an almost total absence of the representatives of the binaphthyl series . This is hardly surprising, for there was no simple and efficient route to NOBIN-like structures until recently.…”

One-pot synthesis of functionalized β-amino sulfides/β-amino selenides via ring opening of cyclic sulfamidates

“…Compounds containing sulfur/selenium and nitrogen have generated profound interest due to their applications in drug design, 1,2 organo catalysis, [3][4][5][6][7][8][9] and medicine [10][11][12] etc. Among these compounds, b-amino suldes have recently received much attention.…”

“…17 Moreover, b-amino suldes/selenides are used as excellent chiral ligands in asymmetric catalysis and hetero bidentate N,S-ligands have proved to be very effective in enantioselective palladium-catalyzed allylic substitution reactions. [4][5][6][7][8][9] In general the synthesis of b-amino suldes/selenides has been achieved using the ring opening of aziridines, [18][19][20] and nucleophilic substitution of amino alcohols derived tosylates by thiolate/in situ generated selenoate anion. 21,22 From our laboratory, we have earlier reported the synthesis of the b-amino suldes/ selenides by ring opening of aziridines by chalocgenide anions generated in situ from dichalcogenides mediated by rongalite (1, sodium hydroxymethanesulnate).…”

Synthesis and application of chiral β‐amino disulfides as ligands for the enantioselective addition of diethylzinc to aldehydes

“…25 In the last few years, a significant improvement in enantioselectivity has been observed by the use of amino sulfur or selenium moieties as catalysts for the enantioselective addition of diethylzinc to aldehydes. [26][27][28][29][30][31][32] Sulfur containing ligands 33 like b-amino thiols and b-amino disulfides derivatives from ephedrine, [34][35][36] norephedrine, [37][38][39] (S)-proline, [40][41][42] (S)-phenylglycine, 43 (S)-valine, 44,45 (R)-cysteine, 5,46-50 (R)-cystine, 51 and others [52][53][54][55][56][57][58] have gained more and more interest as catalysts in this stereoselective reaction. In a similar way, chiral amino diselenides have been efficiently used as catalysts for this addition, [28][29][30][31][32] but due to the most difficult accessibility of these compounds, only a few number of reports can be found in literature.…”