Synthesis of succinimido[3,4-b]indane and 1,2,3,4,5,6-hexahydro-1,5-methano-3-benzazocine-2,4-dione by sequential alkylation and intramolecular arylation of enolates derived from N,N,N ' N '-tetramethylbutanediamides and N,N,N ' N '-tetramethylpentanediamides

The tricyclic title compounds, 4 and 5, were synthesized by initial alkylat ion of the Lithium monoenolates of N,N,N',N'-tetramethylbutanediamide (6) a nd N,N,N',N'-tetramethylpentanediamide (19) with 2-iodobenzyl chloride in l iquid NH3 at -60 degrees C to afford 2-(2-iodobenzyl)-N,N,N',N'-tetramethyl butanediamide (9) and 2-(2-iodobenzyl)-N,N,N',N'-tetramethylpentanediamide (20) in yields of 88 and 87%, respectively. Treatment of 9 with KNH2 in liq uid NH3 resulted in formation and intramolecular arylation of the less-subs tituted or-enolate to produce trans-1,2-bis(N,N-dimethylcarboxamido)indane (10a) in 60% yield. Selective hydrolysis of 10a with aqueous Na2O2 gave tra ns-1-(N,N-dimethylcarboxamido)indane-2-carboxylic acid (17), which was then converted to bridged succinimide 4 by transformation to trans-1-(N,N-dimet hylcarboxamido)indane-2-carboxamide (10c) followed by cyclization of this m ixed primary/tertiary amide by means of NaH in refluxing THF. Treatment of 20 with KNH2 in liquid NH3 led to intramolecular arylation and accompanying ammonolysis to afford trans-1-(N,N-dimethylcarboxamido)-1,2,3,4-tetrahydro naphthalene-3-carboxamide (21b). Conversion of 21b to 5 was similarly effec ted by means of NaH. Experiments designed to test the mechanistic aspects o f the intramolecular arylations provided evidence for competing aryne and S ET pathways.