FUNCTIONALIZED ORGANOLITHIUM COMPOUNDS - GENERATION VIA REDUCTIVE LITHIATION AND NUCLEOPHILIC-ADDITION TO N-PHENETHYLIMIDES - ACCESS TO FUNCTIONALIZED DIHYDROPYRROLO[2,1-A]ISOQUINOLINONES

A procedure for producing 1,4-dianion equivalents consists of reductiv e lithiation, induced by 4,4.-di-tert-butylbiphenylide, of functionali zed phenyl sulfides. Nucleophilic addition of 4-lithio-2-(trimethylsil ylmethyl) but-1-ene 1 and 2-(3-lithiopropyl)-2-trimethylsilyl-1,3-dith iane 2 thus prepared to N-phenethyl-cis-norbor-5-en-2,3-dicarboximide 9 afforded the corresponding alpha-hydroxy lactams in good yields. Bes ides, access to C-10b substituted alpha,beta-unsaturated pyrroloisoqui nolinones 3 was efficiently achieved via a tandem organolithium nucleo philic addition - N-acyliminium ion cyclization sequence and subsequen t retro Diels-Alder reaction. The methodology can be extended to funct ionalized oganolithiums, but the N-acyliminium cyclization fails if th e allylsilane moiety is present. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.