Six- and five-membered 3-alkoxy-2-lithiocycloalkenes:: new stable non-anionic β-functionalised organolithium compounds

Naphthalene-catalysed reductive lithiation of various functionalised chlorocycloalkenes 18 leads to the corresponding non-anionic beta-alkoxyfunctionalised organolithium reagents 14. Their reaction with different electrophiles, such as water, aldehydes, ketones and imines, gave the expected products 19 and 24. The diastereoselection in the reaction with aldehydes can be modified by the use of different additives. In the case of using 3-methoxy-2-chlorocyclopentene (18a) as starting material, and depending on reaction time, unexpected bicyclopentadiene derivatives 25 were isolated, together with the expected compounds 24. (C) 2002 Elsevier Science Ltd. All rights reserved.