O- and p-Hydroxyaryl ketones

Fries rearrangement, review. Martin2 has reviewed the rearrangement of aryl esters to o- and p-hydroxyaryl ketones, usually effected with AICI3. The rearrangement can occur at room temperatures in polar solvents (nitroalkanes). Photo-induced rearrangement usually provides the same products as obtained by Lewis acid induced rearrangement. The review lists 281 references to literature mainly from 1964 to 1990. 

Cumulated yhdes enter into domino addition-intramolecular Wittig olefination reactions with a- and P-hydroxy or amino aldehydes and ketones to afford imsaturated five- and six-membered oxacycles or azacycles, respectively. In this way o-hydroxyaryl aldehydes were converted with 2 into the corresponding annulated pyrans, while pyrrolizines were obtained from 2-acylpyrroles [18]. Fiuther apphcations of this approach have been reported more recently. Andrus et aL [19] prepared the enantiomerically pine pyrrolenone 6 by reaction of yhde 2 with N-Boc protected aldehyde 5 in 60% yield. Plans by this group to use 6 as an intermediate en route to the im-... 

A range of tetrahydro-9f/-xanthen-9-ones arise from photo-induced C-O bond formation of 2-methoxyaryl 2-chlorocyclohex-l-enyl ketones and related compounds (14CC5254). Some examples of tetrahydro-9ff-xanthen-9-ones were obtained as diastereomeric mixtures of cis- and traws-isomers through a 4-DMAP-mediated tandem addition reaction of l-(2-hydroxyaryl)alkynones bearing an aldehyde function (Scheme 76) (140L1642). A Robinson annulation of a P-keto ester and methyl vinyl ketone mediated by tin(lV) chloride afforded a tetrahydro-9H-xanthen-9-one-l-carboxylic acid-type compound (14JOC10689). 

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