Novel intermediates, i.e., N-(2S-(2-propenyl)octanoyl)-(1S)-(−)-2,10-camphorsultam, N-(2S-(2-propynyl)octanoyl)-(1S)-(−)-2,10-camphorsultam and N-(2R-(2-propyl)octanoyl)-(1S)-(−)-2,10-camphorsultam; processes for the preparation of the intermediates; and processes for the preparation of optically active 2S-(2-propenyl)octanoic acid, 2S-(2-propynyl)octanoic acid and 2R-propyloctanoic acid by using the same. Optically active 2R-propyloctanoic acid equivalent or superior to that prepared by the process of the prior art in optical purity can be efficiently prepared in shorter reaction steps.
                            新型中间体,即N-(2S-(2-
丙烯基)辛酰基)-(1S)-(−)-2,10-
樟脑磺内酰胺、N-(2S-(2-
丙炔基)辛酰基)-(1S)-(−)-2,10-
樟脑磺内酰胺和N-(2R-(2-丙基)辛酰基)-(1S)-(−)-2,10-
樟脑磺内酰胺;这些中间体的制备方法;以及利用这些中间体制备光学活性2S-(2-
丙烯基)
辛酸、2S-(2-
丙炔基)
辛酸和2R-丙基
辛酸的方法。通过这种方法,可以高效地在更短的反应步骤中制备出光学纯度相当于或优于现有技术制备的光学活性2R-丙基
辛酸。