t-butyl 5-phenyl-(E,E)-pentadienoate → (3R,alphaS)-t-Butyl 3-(N-allyl-alpha-methylbenzylamino)-5-phenyl-4-pentenoate

Participants

Reaction Steps

The procedure of Example 1 was repeated using (S)-N-allyl-α-methylbenzylamine (2) (0.840 g, 5.22 mmol), 1.6M butyllithium (2.16 ml, 4.17 mmol) and t-butyl 5-phenyl-(E,E)-pentadienoate (19) (0.800 g, 3.48 mmol) as the Michael acceptor. Flash chromatography on silica gel [ethyl acetate/petroleum ether (1:19)] afforded the title compound (20) as a colourless oil (1.33 g, 98%). δH (200 MHz; CDCl3) 7.48-7.21 (10H, m, Ph), 6.48 (1H, d, J=16.0, PhCH=CH), 6.25 (1H, dd, J=16.0 and 7.4, PhCH=CH), 5.85 (1H, m, NCH2CH=CH2), 5.15 (1H, app. dd, J=17.3 and 1.6, trans NCH2CH=CH), 5.07 (1H, app. dd, J=10.3 and 1.5, cis NCH2CH=CH2), 4.09 (2H, m, PhCHCH3 and PhCH=CHCH), 3.22 (2H, d, J=6.1, NCH2), 2.56 (1H, dd, J=14.3 and 6.6, CH2CO2), 2.42 (1H, dd, J=14.3 and 8.2, CH2CO2), 1.43 (3H, m, PhCHCH3), 1.42 (9H, s, (CH3)3C).

Provenance & Evidence