Highly Diastereoselective Pinacol Coupling of Secondary Aliphatic Aldehydes Induced by a Catalytic System Consisting of Vanadium Complex, Chlorosilane, and Zinc Metal

Pinacol Coupling Reaction of Aromatic Aldehydes Mediated by Aqueous Vanadium(II) Solution Under Ultrasound Irradiation

“…reported the stereoselective coupling of two different yet electronically similar aldehydes employing the well-characterized vanadium(II) complex, [V 2 Cl 3 (THF) 6 ] 2 [Zn 2 Cl 6 ]; the major diastereomer in all of the cross coupling reactions is a threo diol. [7] Hirao et al reported highly diastereoselective pinacol coupling of secondary aliphatic aldehydes induced by Cp 2 VCl 3 /R 3 SiCl/Zn, [8] and using VOCl 3 / Me 3 SiCl/Al system, [9] six aromatic aldehydes gave desired pinacols in 49-89% yields. Their diastereoselectivities were high (dl : meso !…”

Enantioselective pinacol coupling reaction of aromatic aldehydes catalyzed by chiral vanadium complexes

“…Recent investigations showed that the type of salan ligands displayed superior asymmetric induction over salen ligands in some reactions [27][28][29][30][31]. On the other hand, although the applications of vanadium compounds in pinacol coupling reaction had been well documented [7][8][9][10], to our knowledge, no chiral vanadium complexes have been used in the reaction in an enantioselective way. Herein we describe the highly asymmetric pinacol coupling of aromatic aldehydes catalyzed by chiral salan-VO(acac) 2 complexes.…”

“…Among various methods explored, the asymmetric pinacol coupling reaction provides a direct way by transforming the achiral aldehydes into chiral 1,2-diols. Although a variety of metals [2][3][4][5][6][7][8][9][10][11][12][13][14][15] had been exploited extensively in the pinacol coupling reaction, these utilizations were mainly focused on the diastereoselective way. Given the fact that both high diastereoselectivity and enantioselectivity should be considered for a successful asymmetric pinacol coupling reaction, this formidable challenge highlights the demand for an efficiently catalytic system.…”

Synthesis of OH-functionalized poly(p-xylylene)s by reductive coupling polymerization of aromatic dialdehydes with catalytic amounts of divalent samarium compounds

“…The structures of all compounds were confirmed by a combination of IR (KBr, Bruker IFS 88 spectrometer), 1 H-, 13 C NMR spectroscopic studies using Bruker AC-200, AC-300 and AMX-500 MHz spectrometers (solvent: (DMSO-d 6 ). Molecular weights of the polymers were determined by gel permeation chromatography (GPC) using Knauer Wellchrom spectral photometer K-2500 and differential refractometer with 1XPSS 8X600 mm/10 lm 10 4 Å and 10 6 Å columns.…”