Diethyl Ether → tert-butyl (1S)-1-formyl-2-methylpropyl(methyl)carbamate

Beteiligte Stoffe

Reaktionsschritte

Lithium aluminum hydride (875 mg, 23 mmol) was added to a solution of Nα-Boc-Nα-methyl-L-valine N-methoxy-N-methylamide (12) (2.0 g, 7.7 mmol) in dry THF (8 mL) and the reaction mixture was stirred for 20 min. The mixture was poured into a stirring solution of potassium hydrogen sulfate (3.14 g, 23 mmol) in water (100 mL). Diethyl ether (75 mL) was added, the layers separated and the aqueous layer extracted with diethyl ether (3×50 mL). The organic layers were combined, and washed sequentially with 3 N hydrochloric acid (3×30 mL), saturated aqueous sodium hydrogen carbonate (3×30 mL), and saturated aqueous sodium chloride (3×30 mL). The organic layer was dried with magnesium sulfate and the solvent was evaporated to yield the crude aldehyde 13 (1.52 g, 92% yield). Aldehyde 13 was used without further purification. Note: 13 can be stored under argon for ˜2 weeks, but when stored in organic solvents at room temperature, undergoes slow decomposition. 1H-NMR (200 MHz, CDCl3) 0.73 (d, J=6.9 Hz, 3H, CH3), 0.91 (d, J=6.9 Hz, 3H, CH3), 1.27 (s, 9H, Boc-(CH3)3), 2.02-2.15 (m, 1H, CH), 2.63 (s, 2H, NCH3), 2.72 (s, 1H, NCH3), 3.44 (d, J=9.5 Hz, 0.5H, CH), 3.86 (d, J=9 Hz, 0.5H, CH), 9.45 (s, 1H, CH); Exact mass calc'd for C11H22NO3 (M+H)+: 216.15997; Found (DCI): 216.15996; Optical rotation obtained was [α]D25 −104.2 (c 5.5, CHCl3).

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