Some studies on carotenoid synthesis.

INTRODUCTION Traditionally synthesis is invoked as the final proof of a structure deduced by other means. In the carotenoid field synthesis is being used increasingly as an integral part of structural studies in order to elucidate some molecular feature for which the other evidence is inconclusive or ambiguous. Synthesis also fulfils the very important role of making many carotenoids much more readily available for further investigations than they would be if it were necessary to rely entirely on natural sources. The variety of natural carotenoids presents many intriguing problems in synth esis, and it is impossible in the space of a short review to do justice to all the work which has been carried out in this field in an attempt to solve them. Attention will therefore be largely confined to problems that have been tackled by the group of which I am, today, the spokesman.