(2S,3S,alphaS)-t-Butyl 3-(N-allyl-alpha-methylbenzylamino)-2-hydroxy-3-phenylpropionate → (2S,4S,5S,alphaS)-2-Ethyl-3-(alpha-methylbenzyl)-4-phenyl-1,3-oxazolidine-5-carboxylic acid t-butyl ester

Participants

Reaction Steps

To a solution of compound (27) from Example 12 (1.039 g, 2.73 mmol) in anhydrous toluene (25 ml) was added tris(triphenylphosphine) rhodium(I) chloride (126 mg, 5 mol %). This solution was refluxed for 4 hours whereafter the toluene was removed under reduced pressure. The residue was treated with diethyl ether, precipitating the catalyst, and the solution was passed through alumina grade 5. After removal of the solvent under reduced pressure, the resulting oil was purified by flash chromatography on silica gel [ethyl acetate/petroleum ether (1:19)] affording the title compound (Rf 0.40) as a colourless oil (0.86 g, 83%). δH (300 MHz; CDCl3) 7.33-7.18 (10H, m, Ph), 4.48 (1H, t, NCHO), 4.38 (1H, d, J=8.0, PhCHCH), 4.21 (1H, d, J=8.0, PhCHCH), 4.01 (1H, q, J=6.9, PhCHCH3), 1.91 (2H, m, CHCH2CH3), 1.27 (3H, d, J=6.9, PhCHCH3), 1.15 (3H, t, J=7.5, CHCH2CH3), 0.99 (9H, s, (CH3)3C).

Provenance & Evidence