M. Bilodeau. D.A. Evans A Survey of Soft Enolization Techniques Chem 115 Alkoxides of lanthanum and yttrium A Survey of Soft Enolization Techniques Sasai. Suzuki. Arai. Arai. Shibasaki J. Am. Chem. Soc. 1992. 114. 4418-4420 PhCHO CI THE Lay(ot-Bu)g(3. 3 mol%), -72 C, 30 h, 74% yield Metal alkoxides Zr(ot-Bu)4( 140 mol%), -50 C, 2.5 h, 86% yield Ti(Ot-Bu)4-No coupling product I. Lewis acid/ amine base enolizations A. Horner-Emmons reactions a Catalytic Enantioselective Aldol Reactions of Nitroalkanes B. Glycine Enolates C Methods for General Carbonyl Substrates Laa(0t-Bu)(3.3 mol%) THE MeNO2, 10 equi D Boron Enolates-Enolate Stereochemistry (S)-Binaphthol (15 mol%) LiCL 20 mol% H 'H NMR shows absence of a t-Butoxy group on the catalys R=C-C6H11, 91% yiel ee Mark bilodeau Evans Group Meeting 3/10/93 Tetrahedron Lett. 1993. 34. 851-854 0 -Naphto 50 equiv -50°c,60h Catalyst prepared from: LaCl 7H20(10 mol%) 80% yield (R)(+)bi de(10m%) H20(10 mol%) 22A-01 Ketone Acidity 11/1/01 3: 41 PMSasai, Suzuki, Arai, Arai, Shibasaki J. Am. Chem. Soc. 1992, 114, 4418-4420. PhCHO + Catalyst THF Ti(Ot-Bu)4 - No coupling product La3(Ot-Bu)9 (3.3 mol%), -72° C, 30 h, 74% yield Y3(Ot-Bu)8Cl (3.3 mol%), -43° C, 3.5 h, 50% yield Zr(Ot-Bu)4 (140 mol%), -50° C, 2.5 h, 86% yield La3(Ot-Bu)9 (3.3 mol%) (S)-Binaphthol (15 mol%) + THF, rt 2 h 1H NMR shows absence of a t-Butoxy group on the catalyst RCHO, 1 equiv MeNO2, 10 equiv LiCl, 20 mol% H2O, 1 equiv R = c-C6H11, 91% yield, 90% ee R = i-Pr, 80% yield, 85% ee R = PhCH2CH2CHO, 79% yield, 73% ee ■ Catalytic Enantioselective Aldol Reactions of Nitroalkanes Sasai, Itoh, Suzuki, Shibasaki Tetrahedron Lett. 1993, 34, 855-858. Tetrahedron Lett. 1993, 34, 851-854. 1 equiv + MeNO2 50 equiv Catalyst -50° C, 60 h LaCl3•7H2O (10 mol%) (R)-(+)-binaphthoxide (10 mol%) NaOt-Bu (10 mol%) H2O (10 mol%) Catalyst prepared from: 80% yield 92% ee Alkoxides of Lanthanum and Yttrium Mark Bilodeau Evans Group Meeting 3/10/93 A Survey of 'Soft' Enolization Techniques D. Boron Enolates - Enolate Stereochemistry I. Metal Alkoxides II. Lewis Acid/ Amine Base Enolizations A. Horner-Emmons Reactions B. Glycine Enolates C. Methods for General Carbonyl Substrates M. Bilodeau, D.A. Evans A Survey of 'Soft' Enolization Techniques Chem 115 O Me Cl Me O Ph HO Cl NO2 R HO α−NaphtO NO2 OH α−NaphtO CHO 22A-01 Ketone Acidity 11/1/01 3:41 PM