Efficient, large-scale preparation of (R)- and (S)-1-(2,4,6-triisopropylphenyl)ethanol, versatile chiral auxiliary for cyclopentenone, γ-butyrolactone, and γ-butyrolactam synthesis

B(C6F5)3‐Catalyzed Reduction of Ketones and Imines Using Silicon‐Stereogenic Silanes: Stereoinduction by Single‐Point Binding

“…General Information: B(C 6 F 5 ) 3 (1), [25] rac-8 and ( Si R)-8, [14b] ketones 15, [26] 16 [27] and 26, [28] silanes 31 [29] and 32, [30] imines (E/Z)-37 [31] and 42, [32] silicon-stereogenic silanes rac-39 [33] and rac-41 [34] were prepared according to known procedures. All reactions were performed in flame-dried Schlenk tubes under a static pressure of argon using conventional Schlenk technique or a glovebox.…”

SmI2‐Induced Umpolung of the CN Bond: First Reductive Conjugate Addition of Nitrones to α,β‐Unsaturated Esters

“…When the 1‐(triisopropylphenyl)ethyl auxiliary26 was used, an excellent diastereoselectivity (>95:5) was observed (Table 2, entry 6); a single‐crystal X‐ray crystallographic analysis of the major diastereomer provided its relative configuration 27…”

Asymmetric Access to α‐Substituted Functional Aspartic Acid Derivatives by a [3+2] Strategy Employing a Chiral Dienophile

“…The pure E geometry of the crystalline nitrone 6b (m.p. [8] This study was extended to chiral benzyl vinyl ethers 7a, [11] originating from (R)-1-phenylethanol, and 7b, derived from (R)-or (S)-1-(2,4,6-triisopropylphenyl)ethanol [12] (Stericol ® ). Importantly, in view of the analogies displayed in the NMR spectroscopic data, this also confirms the assignment of pure E geometry to 6a and to the other Nbenzyl nitrones described previously.…”

“…In our previous report, thermal 1,3-dipolar cycloadditions (1,3-DCs) between nitrone 6a and vinyl ethers derived from (-)-menthol, d-(-)-pantolactone, and (R)-methyl mandelate were found to proceed in high yields but with low diastereoselectivities. [8] This study was extended to chiral benzyl vinyl ethers 7a, [11] originating from (R)-1-phenylethanol, and 7b, derived from (R)-or (S)-1-(2,4,6-triisopropylphenyl)ethanol [12] (Stericol ® ). For the preparation of O-vinyl ethers 7b, the previously employed two-step method involving the formation of a dichlorovinyl ether [13] (Table 1, Entry 1) was compared with direct O-vinylation procedures.…”