Acyl-Claisen rearrangement

Scheme 2.153. Yb(OTF)3-promoted domino ketene addition/acyl-Claisen rearrangement.

SCHEME 17.20. MacMillan s enantioselective acyl-Claisen rearrangement. 

H-Azepine, 2-allyloxytetrahydro-Claisen rearrangement, 7, 508 3H-Azepine, 2-amino-acylation, 7, 511 effect of acidification, 7, 510 nucleophilic displacement reactions, 7, 514 synthesis, 7, 533, 535 3H-Azepine, 2-amino-7-bromo-synthesis, 7, 529 3H-Azepine, 2-anilino-ring inversion, 7, 495-499 structure, 7, 533... 

Allylation of the 7-hydroxyquinoline derivative 242 with allyl bromide gave the corresponding 7-allyl ether 243 which underwent Claisen rearrangement to give the 8-allyl derivative 244. Acylation and subsequent bromination afforded the dibromopropyl derivative 245. Treatment of 245 with KOH/EtOH gave 8-hydroxypyrroloquinoline 246 that was methylated with methyl iodide to afford 247 (91JOC980) (Scheme 44). 

Hydroxyalkyl)porphyrins,84-85 I07b 109 easily accessible from porphyrins by Friedel-Crafts acylation and subsequent reduction, undergo a stereoselective Claisen rearrangement with N,N-dimethylacetamide dimethyl acetal. The substitution pattern and the stereochemical arrangement of the derived chlorins match those of naturally occurring chlorins9 (see Section 1.2.1.2.). 

The strategy for the synthesis of y-butyrolactones by Claisen rearrangement of acylated 1,4-diols has been already discussed (Schemes 6-11). A stereodi-... 

Langlois and co-workers ° developed a stereoselective hetero-Claisen rearrangement of camphor-based oxazoline A -oxides 300, available from hydroxylami-noisobomeol 298 and orthoesters 299. The rearrangement, initiated by acylation of... 

Usually, one would expect that an acrylate ester would be prepared by the acylation of an alcohol with acryloyl chloride. Jonathan M.J. Williams of the University of Bath reports (Tetrahedron Lett. 44 5523,2003) that this acylation can also be effected with the mild combination of Ph,P and maleic anhydride. The acrylate esters so prepared are interesting as polymerization precursors, and as Diels-Alder dienophiles. The allylic acrylates invite tandem conjugate addition / Ireland Claisen rearrangement. 

Tetrafluoroethene has been used as a 2-carbon difluoroacetic acid equivalent, methodology developed by Normanl and co-workers, in the synthesis of inhibitors of Cobra venom phospholipase A2.13 Conversion of the allyl alcohols into the 2,2-difluoropent-4-enoic acids 32 is performed in one pot. The crude acids 32 are then converted into the methyl esters 33. Although esters 33 can be obtained directly from the acyl fluorides 29, as originally described by Normant and co-workers,10 a two-step procedure facilitates the workup after the Claisen rearrangement. 

Cyclization of Af-acylated 3-aminopropanol derivatives131,13a and of urea derivatives133 belongs to the same category of reactions as do cyclization of isothioureas13 and a novel cyclization followed by Claisen rearrangement of 37 into 38135 [Eq. (26)]. 

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