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

Abstract

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 PotentialHerrn 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 2H1‐pyran‐2,4(3H)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‐N1‐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 N1‐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 N1‐phenyl‐1‐sulfinyl‐22 and N1‐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 N1‐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.