1,3‐Donor/Donor‐substituierte Allene, VII Allencarboxanilide durch Umallenierung oder [2.3]/[3.3]1‐sigmatrope Umlagerungen Bausteine mit vielseitigem intra‐und intermolekularem Synthesepotential

1,3‐Donor/Donor‐Substituted Allenes, VII [1] . – Allenecarboxanilides by Transallenation or [2.3]/[3.3]1‐Sigmatropic Rearrangements – Building Blocks with Versatile Intra‐and Intermolecular Synthetic Potential Herrn Professor Richard P. Kreher zum 60. Geburtstag gewidmet. The reaction of 1,3‐bis(alkylarylamino)1‐1,3‐diethoxyallenes 1,2 with disubstituted malonyl chlorides 3 leads to N, N ′1‐dialkyl‐ N, N ′1‐diarylallene‐1,1‐dicarboxamides 4, 5 , and 2 H 1‐pyran‐2,4(3 H )1‐diones 6, 7 , respectively, with a transallenation reaction being favoured in the case of allene 1 . Thermal tandem cyclisation of allene‐1,1‐dicarboxanilide 4c via 2‐quinolone 8 affords phenanthridone 9 . Spontaneous acylcycloalkane/cycloenol ether isomerisation of spirane 6b gives pyrane 12 . Thermally induced ( Z)1‐anilinoacryclic acid/quinolone cyclisation of pyranes 6a, 12 , and 7 leads to 4‐quinolones 11, 13 , and 14 . Propargyl THP ether 15 reacts with carbamoyl chloride 16 to yield alkinol‐ N 1‐phenylanilides 17 . Alkinol 17a reacts with sulfinyl chloride 18 to yield sulfinic ester 19 , which on heating undergoes a [2.3]1‐sigmatropic rearrangement to N 1‐phenyl‐1‐sulfonylallene‐1‐carboxanilide 20 . Reaction of alkinols 17 with sulfenyl chlorides 21 or chlorophosphanes 23 , followed by [2.3]1‐sigmatropic shift, affords N 1‐phenyl‐1‐sulfinyl‐ 22 and N 1‐phenyl‐1‐phosphorylallene‐1‐carboxanilides 24 , respectively. Alkinyl ketene acetal intermediates 26 are formed starting from alkinol 17a and orthoesters 25 . Spontaneous [3.3]1‐sigmatropic rearrangement of 26 gives N 1‐phenylallene‐1‐carboxanilides 27 . Intramolecular Diels‐Alder (IDA) reactions of the allene‐1‐carboxanilides 27 lead to [2.2.2]bicycles 28 . Contrarily, the IDA intermediates of 20b and 24 further isomerize to the [3.2.1] bicycles 29 and 30 . The allenyl sulfoxides 22 readily undergo Michael‐type reactions with CH‐acidic compounds 31 to give allyl sulfoxides 32 . Among these, only 32d can be isolated, whereas 32a–c spontaneously rearrange in a four‐step reaction cascade to butenolides 33a–c . A Michael‐type reaction of (diethoxyphosphoryl)allenes 24 with α1‐hydroxy ketones 34 followed by a Horner‐Emmons reaction leads to alkylidene‐dihydro‐furans 35 , which isomerize in the presence of a base to yield furans 36 . Analogously, allenes 24 react with 2‐hydroxybenzaldehydes 37 or 2‐pyrrole‐/2‐imidazole derivatives 40 to form alkylidenechromenes 38 and pyrrolizines/pyrroloimidazoles 41 , respectively. Benzopyrylium salts 39 are accessible from chromenes 38 and perchloric acid.