Synthesis of enantiomerically enriched tertiary 2-cyclohexene-1-thiols via configurationally stable alpha-thio-substituted allyllithium compounds.
[reaction: see text] (S)-S-(2-Cyclohexenyl) N,N-diisopropylmonothiocarbamate [(-)-(S)-8] was deprotonated by sec-butyllithium/TMEDA to form a configurationally stable lithium compound (S)-9, which is the first example of a new class of alpha-thio-substituted organolithium compounds with improved properties. It is regioselectively alkylated by alkyl halides with complete stereoinversion to form the monothiocarbamates (+)-10 which afford highly enantioenriched tertiary 2-cyclohexene-1-thiols (+)-6 on reductive cleavage.
Marr
Felix
F
Organisch-chemisches Institut der Universität, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany.
Hoppe
Dieter
D