Synthesis of the Chiral (8S)-7-Aza-1,3(E),9-decatriene System from Natural α-Amino Acids and Its Intramolecular Diels-Alder Reaction Directed toward Chiral trans-Hydroisoquinolones

Article abstract of DOI:10.1021/jo00278a024

L-Alanine and L-valine were converted into optically active 7-aza-1,3(E),9-decatrienes containing a (tert-butyldimethylsilyl)oxy group at C(2) and a methyl or isopropyl group at C(8).Intramolecular thermal <4 + 2> cycloaddition reactions of these trienes gave optically active trans-nonahydro-6(2H)-isoquinolones.The relatively bulky isopropyl group at C(8) increased the trans selectivity in the ring closure.These results are in contrast with literature reports on ring closure of analogous aza trienes that lack the (tert-butyldimethylsilyl)oxy group at C(2), whichgive predominantly cis-fused rings.