Dichlorotitanium diisopropoxide

TADDOLates (lb) and (le) are prepared from (2) and Dichlorotitanium Diisopropoxide, without removal of the i-PrOH formed (eq 2). They are typically used in the presence of 4 Xmolecular sieves. ... 

Cycloadditions of Acrylate Derivatives. Acrylate derivatives undergo highly stereoselective Diels-Alder cycloadditions with 1,3-dienes when promoted by a Lewis acid, Dichlorotitanium Diisopropoxide or Jitanium IV) Chloride (eq 2). With the latter, care must be taken to avoid... 

A little dichlorotitanium diisopropoxide in toluene added to a mixture of activated, powdered, 4A molecular sieves and a little (R)-2,2 -dihydroxy-1,1 -binaphthyl in methylene chloride at room temp, under argon, the mixture stirred for 1 h, cooled to — 70°, isobutylene and methyl glyoxylate added, warmed to — 30°, and stirred for 8 h - (R)-product. Y 72% (e.e. 95%). Molecular sieves facilitate ligand exchange on the metal and play a role in maximizing the stereodifferentiating ability of the catalyst (e.e. ca. 20% without sieves). F.e.s. K. Mikami et al., J. Am. Chem. Soc. Ill, 1940-1 (1989) from chiral pyruvic acid esters with TiCl4 cf. J.K. Whitesell et al., J. Org. Chem. 54, 2258-60 (1989) review of C2-symmetry and asym. induction s. Chem. Rev. 89, 1581-90 (1989). 

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