Novel Asymmetric Alkylation of Aromatic Aldehydes with Triethylaluminum Catalyzed by Titanium·(1,1‘-bi-2-naphthol) and Titanium·(5,5‘,6,6‘,7,7‘,8,8‘-octahydro-1,1‘- bi-2-naphthol) Complexes

Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)‐h8‐binol

“…The same phenomena have also been observed for the aryl addition of p-tolylLi, 34 AlPh 3 (THF), 24,27 or AlPhEt 2 (THF) 28 to benzaldehyde or 2-methylbenzaldehyde (entries [13][14][15]. This study shows that addition reactions of RTi(O-i-Pr) 3 produced desired products having the same stereochemistry (entries [15][16][17]. The above observations illustrate that substituents at 3-position or 3,3 0 -positions of the BINOLate ligands do not affect the stereochemistry of the major products.…”

“…[1][2][3][4] Over the past two decades, a variety of chiral ligands have been developed to deliver desired alcohols in high enantioselectivities. [5][6][7][8][9][10][11][12][13][14][15][16] Recent studies have shown that organoaluminum compounds are effective reagents, [17][18][19][20][21][22][23][24][25][26][27][28][29] and addition reactions can even be completed in 10 min. 24 Grignard [30][31][32][33] and lithium 34 reagents have also been established recently as efficient nucleophiles for addition reactions despite their high reactivity.…”

1,3‐bis[N‐sulfonyl‐(1R,2S)‐1,3‐diphenyl‐2‐aminopropanol]benzene: An excellent ligand for titanium‐catalyzed asymmetric AlPh3(THF) additions to aldehydes

“…32 Organoaluminum compounds are more reactive than organozinc or organoboron reagents and have been applied to diversified organic syntheses [33][34][35][36][37][38][39][40][41] and to asymmetric catalytic reactions. [42][43][44][45][46] To continue our effort to develop amino alcohol ligands [47][48][49][50] for asymmetric catalytic reactions and also to demonstrate the application of AlAr 3 (THF) compounds, we herein report asymmetric AlPh 3 (THF) additions to a variety of aldehydes catalyzed by an in situ formed titanium(IV) catalyst of 1,3-bis[N-sulfonyl-(1R,2S)-1,3-diphenyl-2-aminopropanol]benzene (1). Compound 1 has been reported to be an excellent ligand in titanium-catalyzed ZnEt 2 additions to aldehydes.…”

Highly enantioselective alkynylation of aldehydes using a new BINOL/Ti(OiPr)4/chiral sulfonamide catalyst system

“…The catalytic system was substantially less effective for aromatic substrates. On the basis of our previous study on the chiral-Ti-BINOL and Ti-H 8 -BINOL catalyzed addition of diethylzinc and triethylaluminum to aldehydes, 11,12 we studied the asymmetric alkynylzinc addition to aldehydes with a catalyst prepared in situ from titanium tetraisopropoxide and (R)-H 8 -BINOL. 13 A similar system was also reported by Pu and coworkers 14,15 and gave high ees for the desired products.…”