| abstract |
The invention relates to a process for the production of vinyl chromanes. This process involves the preparation of the compounds of the formula where R ° is hydrogen or a removable protective group, and is characterized in that a compound of the formula wherein R ° has the above meaning and R¹ represents the radical -CH₂-CH₂-C (W) (CH₃) -CH = CH₂ or CH₂CH₂-C (CH₃) = CH-CH₂-W, where W is a leaving group, cyclized using a chiral transition metal diphosphine complex.n n n The compounds I are valuable intermediates, for example suitable for the preparation of (R, R, R) -α-tocopherol. |