f) Pergamon PII: S0040-4020(97) 10141-7 letrahedron, Vol..53, NO..50, pp. 17201-17210, 1997 O 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0040-4020/97 $17.00 + 0.00 Funetionalised Propargyllithium Reagents Cecilia G6mez, Fernando F. Huerta, Isidro M. Pastor and Miguel Yus* Departamento de Quimica Org,4nica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain Abstract : The reaction of chlorinated acetylenic ether or amines I with lithium and a catalytic amount of DTBB (5%), in the presence of different electrophiles [priCHO, ButCHO, PhCHO, Me2CO, (CH2)5CO, Me3SiCI] in THF at -78 or -105°C leads, after hydrolysis with water, to the corresponding products 2. The same process applied to the previously deprotonated chloroalcohol 4a or the secondary amine 4b can be carried out in a two-step reaction giving the expected products 6 by using several electrophiles [PrJCHO, ButCHO, PhCHO, Me2CO, (CH2)5CO, Me3SiCI] at-78°C. © 1997 Elsevier Science Ltd. INTRODUCTION An inherent problem concerning both nucleophilic or electrophilic propargylic substitution is that this process can yield the expected propargylic product of the type I, together with the corresponding allenic system of the type II, this last one being in many cases the most important. A B R A Nu I II A B A E + I II When at the other propargylic position is a heteroatom, the corresponding organometallic species are, in general, unstable due to their tendency to suffer decomposition, even at low temperatures, to give a 8- elimination reaction which, for instance in the case of the corresponding organolithium compound III, would give a cumulenic compound IV.I 17201