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A new single-step efficient photocchemical approach for α-arylpropanoic acids ( 4 ) from α chloro-propiophenones ( 5 ) is described. It involves carbonyl triplet excited state directed 1,2-aryl migration of the aryl group which has been found to be highly dependent upon the nature of the aryl substituent. The mode of this rearrangement is probed by the study of the photobehaviour of a set of optically active α-chloro-propiophenones. The results suggest that the nature of the carbonyl triplets (n,π * /π,π * ) plays an important role in the chirality transfer. This method finds application in the synthesis of optically active ibuprofen ( 4e ) and ketoprofen ( 26 ), though in moderate optical yields.

A regiospecific synthesis of bikaverin (1) is described starting from methyl 2-hydroxy-4-methoxy-6-methyl benzoate (2) and 2-chloro-5,7-dimethoxy-1,4-naphoquinone (4).

Synthesis of (±)heritol and epi -heritol is described. The key step is the osmylation of the unsaturated ester 9a. Osmylation is used as a tool to construct the α,β-unsaturated γ-lactone system.

Stereoselective synthesis of (±)-diacetylobafluorin and (+)-SQ 26,517 has been accomplished via transacylation of α-N-(2-nitrophenyl)sulphenyl-β-lactones with 2-acylmercaptobenzothiazoles.

A strategy based on photochemical 1,2-aryl migration as the pivotal step allows efficient transformation of 2-chloro-propiophenones into 2-arylpropionic acids. A noticeable substituent-directed excited state control on the rearrangement process has been observed.

A short, convergent synthesis of (±) patulolide A, a 12-membered macrolide with high antifungal activities is hereby reported. It has been achieved in 10 steps from 1-bromopentanal and 4-hydroxypent-1-yne.

1:3:8-Trihydroxy-2-hydroxymethylanthraquinone has been synthesised by hydroxymethylation of 1:3:8-trihydroxyanthraquinone and shown to be different from versicolorin, the colouring matter isolated by Hatsuda and Kuyama from Aspergillus versicolor. Damnacanthol and damnacanthal, the colouring matters of the roots of Damnacanthus major and D. indicus have been synthesised by a new route.

A novel route to the model spiro-compound 4, for Fredericamycin A (1) is reported, which involves the use of PTC for activating indenyl anion nucleophilicity. A parallel photo-route to 4, from 9 and (or) 10 is described.

Synthese a partir d'hydroxy-2' tetramethoxy-3',4',5',6' propiophenone via la dimethyl-2,3 tetramethoxy-5,6,7,8 chromone