Lithium Bromide → HCID 58208585, compound

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of lithium bromide (596 mg, 6.85 mmol) and tosylate (91a) (0.68 g, 2.28 mmol) in dimethylformamide (5 mL) was heated at 110° C. for 1 hour, then at 125° C. for 1.5 hours, then at 130° C. for 2 hours under an atmosphere of argon then diluted with water (20 mL). The product was extracted into diethyl ether (4×10 mL) then the combined organic layers washed with water (3×10 mL), brine (10 mL), dried (MgSO4), filtered and reduced in vacuo to leave an orange oil. Flash chromatography over silica, eluting with ethyl acetate:heptane mixtures 0:100 to 35:65 gave bromide (92) as a colourless oil (292 mg, 62%). TLC (Rf=0.80, EtOAc:heptane 1:2), [α]D20.5+75.2° (c=1.13, CHCl3); δH (500 MHz, CDCl3) 1.10 (3H, d, J=6.80 Hz, CH3CH), 2.24-2.33 (1H, m, CH3CH), 3.30 (1H, dd, J=11.23 and 8.20 Hz, 1×CH2CHCH3), 4.13 (2H, m, CH2CHBr), 4.20 (1H, t, J=7.99 Hz, 1×CH2CHCH3), 4.28-4.30 (1H, m, CHBr), 4.68 and 4.74 (2H total, t, J=3.87 Hz and dd, J=3.55 and 0.92 Hz respectively, BrCHCHCHO); δC (125 MHz, CDCl3) 9.842 (CH3CH), 39.904 (CH3CH), 51.616 (CHBr), 74.993 and 76.118 (CH2CHBr and CH2CHCH3), 84.708 and 89.891 (BrCHCHCHO).

Provenance & Evidence