Methyl allenecarboxylate

The photocycloaddition of 2tf-azirines to electron-deficient olefins produces d -pyrrolines as primary photoproducts. Some of the dipolarophiles used include acrylic esters, acrylonitriles, fumaric and maleic esters, methyl allenecarboxylate, norbornene, and l,2-dicyanocyclobutene. Similarly, styrenes and vinylpyridines undergo smooth photocycloaddition to 2H-azirines. Addition of acetylene derivatives to the transient nitrile ylide gives 2H-pyrroles (18, 20) which rearrange to pyrroles (19) if the C-2 atom is monosubstituted. 3-Phenyl-2/f-azirines have been found to cycloadd to vinylphosphonium salts and to vinyl sulfones. The initial adducts (22 and 24) undergo ready loss of the phosphorous or sulfur substituent to give 2H-pyrroles (23 and 25). ... 

Cyclic methyl allenecarboxylates containing 9—12 carbon atoms in the ring can be obtained from cycloalkanones of the same ring size by an extension of a method first reported in 1972. ... 

Penta-2,3-dienoic acid 3-methyl-l -allenecarboxylic acid) (70) Total electron density 367,368 ... 

MO calculations show that the diradical stepwise pathways are preferred over the concerted paths in the Diels-Alder cycloaddition of strained allenes, such as cyclohexa-1,2-diene, with cyclobuta-l,3-diene. An ab initio study of the regio- and stereo-selectivity of the Diels-Alder reaction of vinylallenes and methyl-substituted vinylallenes with acrolein showed the reactions to be asynchronous. Allenamides undergo inverse-electron-demand 4 - - 2-cycloaddition with alkyl vinyl ketones to yield pyranyl ketones. The cycloaddition of (silyloxyvinyl)cyclohexene (147) with the allenecarboxylate (148) produced the exo-cycloadduct (149), which is a key intermediate in the total synthesis of the phosphatase inhibitor dysidiolide (Scheme 57). ... 

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