C45‐ und C50‐Carotinoide. 4. Mitteilung. Synthese von optisch aktiven cyclischen C20‐Bausteinen und von (2R,2′R)‐2,2′‐Bis(4‐hydroxy‐3‐methyl‐2‐butenyl)‐β,β‐carotin ( = C.p. 450)

C45‐ and C50‐Carotenoids: Synthesis of Optically Active Cyclic C20‐Building Blocks and of (2R,2′R)‐2,2′‐Bis(4‐hydroxy‐3‐methyl‐2‐butenyl)‐β,β‐carotene ( = C.p. 450) The synthesis of the optically active C20‐building blocks (R)‐26 and (R)‐39 and of the optically active cyclic C50‐carotenoid C.p. 450 (3) starting from (−)‐β‐pinene is reported.