Synthesen in der Carotinoid‐Reihe. 17. Mittelung. γ‐Carotin sowie d , l ‐α‐ und β‐Carotin aus Dehydro‐β‐apo‐12′‐carotinal(C 25 )

γ‐Carotene (m. p. 153°) has been synthesized by a W ITTIG reaction of either dehydro‐β‐apo‐l2′‐carotenal(C 25 ) (V) with pseudo‐ionylideneethyl‐triphenylphosphonium chloride (IV) (C 25 + C 15 = C 40 ) or of β‐apo‐8′‐carotenal(C 30 ) (VII) with geranyltriphenylphosphonium bromide (VIII) (C 30 + C 10 = C 40 ).