An Unprecedented Asymmetric Nazarov Cyclization for the Synthesis of Nonracemic Indanes as Endothelin Receptor Antagonists

All articles of this category An asymmetric synthesis of the novel nonracemic endothelin receptor antagonists, SB 209670 ( 1 a ) and SB 217242 ( 1 b ) is described which utilizes an unprecedented asymmetric Nazarov-type ring closure of the alkylidene-1,3-carbonyl compounds. Excellent 1,5-induction is observed which establishes the required S configuration at the C-3 carbon of an indane skeleton. asymmetric Nazarov cyclization - 1,5-asymmetric induction - endothelin receptor antagonists - indanes