Propionaldehyde tert‐Butylimine

(R = t-Bu) [7020-81-7] C7H15N (MW 113.23) InChI = 1S/C7H15N/c1-5-6-8-7(2,3)4/h6H,5H2,1-4H3 InChIKey = WTXVHWJXWDLITB-UHFFFAOYSA-N (R = t-Bu, Li salt) [75261-61-9] C7H14LiN (MW 119.16) InChI = 1S/C7H14N.Li/c1-5-6-8-7(2,3)4;/h5H2,1-4H3; InChIKey = NYHCFMDKQYDGOY-UHFFFAOYSA-N (R = Cy) [6898-80-2] C9H17N (MW 139.27) InChI = 1S/C9H17N/c1-2-8-10-9-6-4-3-5-7-9/h8-9H,2-7H2,1H3 InChIKey = GVXRFUBCUFQTFF-UHFFFAOYSA-N (two-carbon nucleophile in enolate alkylations, conjugate addition reactions, and directed aldol condensations; especially useful for α-monoalkylations and three-carbon homologations1) Physical Data: R = t-Bu: bp 103 °C,2 48–50 °C/115 mmHg,3 47–49 °C/95 mmHg.4 R = Cy: bp 63–64 °C/15 mmHg,4 62–63 °C/12 mmHg;5 n16D 1.4450. Solubility: sol THF, ether, CCl4, pentane, benzene, toluene. Form Supplied in: colorless liquid when freshly distilled; darkens on prolonged standing Analysis of Reagent Purity: NMR or IR. Preparative Methods: the general method adapted by Stork and Dowd from the procedure developed earlier by Tiollais is said to be highly efficient for the synthesis of aldimines from low-boiling aldehydes.2 Quantitative yields have also been reported when propanal is added to a preformed amine–Titanium(IV) Chloride complex.6 Lithiopropionaldehyde t-butylimine is usually prepared by reaction with a slight excess of a hindered nonnucleophilic base like Lithium Diethylamide in THF or ether at −78 °C under N2 or argon.7, 8 A variation of this method calls for addition of Hexamethylphosphoric Triamide to the reaction mixture.8b Handling, Storage, and Precautions: best used when freshly prepared. Imines can be distilled, but they tend to polymerize upon long standing. Stored samples are distilled over KOH to remove high-boiling condensation products prior to use. Storage as neat liquids is not recommended for long periods, but solutions in dry THF (0.4 M) can be stored at −20 to −30 °C with minimal deterioration.9 In acidic solutions, the imine reverts to propanal and the amine. The lithiated imine is generally prepared in situ under N2 or argon. Use in a fume hood.