Isolation of 9Z beta-carotene from Dunaliella bardawil and its stereoselective synthesis.

An isolation of 9Z beta-carotene from Dunaliella bardawil was accomplished by low-pressure column chromatography with Ca(OH)2 column. Furthermore, it was stereoselectively synthesized by Wittig reaction between the C10-phosphonium salt 2 and 9Z beta-apo-8'-carotenal 1, which was prepared by Emmons-Horner reaction of 9Z beta-ionylideneacetaldehyde 3 with phosphonates 6 and 7 or 8a and 9.