Partial Synthesis and Characterization of Capsokarpoxanthins and 3,6‐Epoxcapsanthins

The acid‐catalyzed hydrolysis of (3 S ,5 R ,6 S ,3′ S ,5′ R )‐5,6‐epoxycapsanthin ( 5 ) led to (3 S ,5 R ,6 R ,3′ S ,5′ R )‐( 7 ) and (3 S ,5 R ,6 S ,3′ S ,5′ R )‐capsokarpoxanthin ( 8 ). In addition, (3 S ,5 R ,8 R ,3′ S ,5′ R )‐ ( 9 ), (3 S ,5 R ,8 S ,3′ S ,5′ R )‐capsochrome ( 10 ), and (3 S ,5 R ,6 R ,3′ S ,5′ R )‐3,6‐epoxycapsanthin ( 6 ) afforded (3 S ,5 S ,6 R ,3′ S ,5′ R )‐capsokarpoxanthin ( 12 ) (3 S ,5 S ,8 S ,3′ S ,5′ R )‐ ( 13 ) and (3 S ,5 S ,8 R ,3′ S ,5′ S )‐capsochrome ( 14 ) as well as (3 S ,5 S ,6 R ,3′ S ,5′ R )‐3,6‐epoxyepicapsanthin ( 15 ). Compounds 5 – 15 were isolated in crystalline form and characterized by their UV/VIS, CD, 1 H‐ and 13 C‐NMR, and mass spectra.