Dsm IP Assets B.v.

Marc-André Mueller

Werner Bonrath

Thomas Netscher

Bettina Wuestenberg

Viktor Zimmermann

Raphael Beumer

Bettina Wüestenberg

Jonathan Alan Medlock

Andreas Pfaltz

Theodor Zweifel

Fabrice Aquino

Felix Imberi

Christina Smuda

The present invention relates to a new process for the production of new specific intermediates, which are preferably used in the production of vitamin A, vitamin A acetate, or β-carotene and derivatives thereof, e.g. canthaxanthin, astaxanthin or zeaxanthin.

Process for production of new sulfolenic intermediates

The present invention relates to a new process for the production of vitamin A and/or its derivatives.

Process for production of vitamin A

The present invention relates to a new compound and the dehydrogenation of that compound to produce retinal.

Dehydrogenation process

The present invention relates to a new process for the production of retinal or hydrogenated form of retinal.

Process for the production of retinal

The application relates to a process for the preparation of a compound of formula (II) by cyclisation of a polyene of formula (I), and to an intermediate of formula (III). The obtained compounds are useful intermediates in the preparation of specific isoprenoids, preferably in the production of vitamin A and derivatives of vitamin A.

Process for the preparation of intermediates for the synthesis of vitamin A derivatives from polyenes by cyclisation

Processes for synthesizing new compounds that may usefully be employed in organic synthesis, especially in the synthesis of vitamin A or β-carotene and derivatives thereof, e.g. canthaxanthin, astaxanthin or zeaxanthin are disclosed. The new compounds are especially useful as intermediates (building blocks) in the synthesis of vitamin A or β-carotene, preferably vitamin A.

Intermediates for the vitamin A synthesis

The present invention relates to a new dehydrogenation process of specific compounds.

Specific dehydrogenation process (I)

The present invention relates to a process for the production of &#x3b2;-springene of formula (I) wherein a compound of formula (II) is heated in the presence of a catalyst. 

Process for the production of beta-springene

The present invention relates in a first aspect to a process for hydrogenation of ketones having at least a carbon-carbon double bond in the y,8-position to the keto group by hydrogen in the presence of at least one chiral iridium complex of formula (I), where R1 represents a group of formula (II) or (III) or (IV). It has been shown that this process leads to a strong increase in preferential formation of a single isomer. The process is particularly suitable for the hydrogenation of y,8-unsaturated ketones which can be used as flavors and fragrances or for the preparation of vitamin E and its derivatives or of flavors and fragrances. 

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Kaiseraugst, Switzerland

Marc-André Mueller