Hydrochalcogenation of activated olefines. Synthesis of functionalized dialkylchalcogenides João V. Comasseto a, * , Rogério A. Gariani a , Jefferson L. Princival a , Alcindo A. Dos Santos b , Fabiano K. Zinn a a Instituto de Quı ´mica, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-900 São Paulo, SP, Brazil b Departamento de Quı ´mica, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil article info Article history: Received 14 May 2008 Received in revised form 9 June 2008 Accepted 9 June 2008 Available online 17 June 2008 Keywords: Alkanethiols Alkaneselenols Alkanetellurols Dialkylsulfides Dialkylselenides Dialkyltellurides abstract Alkanethiols, selenols and tellurols are generated in situ by reaction of elemental sulfur, selenium and tel- lurium with commercial alkyllithiums, followed by reaction with deoxygenated water. The alkanechalc- ogenols react in situ with activated olefins in a Michael-type addition reaction. Ó 2008 Elsevier B.V. All rights reserved. 1. Introduction Organic compounds of sulfur [1], selenium [2] and tellurium [3] present useful synthetic applications. Notwithstanding their syn- thetic potential, the organic compounds of these elements, spe- cially those containing selenium and tellurium, are avoided by the synthetic organic chemists. The bad reputation of these ele- ments many times arises from comments found in the literature concerning the bad smell of the organic chalcogen compounds. A long time concern of our laboratory is the development of experi- mental protocols which avoid the manipulation of bad smelling organochalcogen compounds [4]. We could conclude that some of the comments on the bad smell of such compounds are effec- tively true, but only for the low molecular weight representatives of specific classes of the organochalcogen compounds. Once incor- porated into a more complex structure, the bad smell of the organ- ochalcogen compound varnishes or disappears, giving rise to products which present smell not more unpleasant than most of the chemicals found in an organic synthesis laboratory. Among the very bad smelling organochalcogen compounds of large synthetic use are the alkanethiols and selenols and low weight non-functionalized dialkylditellurides, precursors of metal alkane- tellurolates and alkanetellurols. In the last years our laboratory has been devoted to develop friendly conditions to generate and use these reagents in situ, so avoiding their manipulation in the labora- tory atmosphere. We found that most of the products resulting from the interaction of alkanethiols, –selenols and –tellurols (tellurolates) with organic substrates are easily isolated as non- bad smelling synthetic intermediates. In this paper we give a full account of the scope and limitations of the in situ generation and use of low molecular weight alkanethiols, –selenols and –tellurols in Michael-type addition reactions to electron-deficient olefins. 2. Results and discussion The reaction of elemental sulfur with alkyllithiums is a long known method to prepare thiols [5]. However, nowadays this reac- tion is rarely used to prepare this class of organosulfur compounds. In this work we observed that elemental sulfur suspended in THF reacts rapidly with n butyllithium giving initially an orange solu- tion, which becomes limpid and colorless after reaction with stoi- chiometric amount of n butyllithium. The initially observed orange color is probably due to the initial formation of lithium alkylpoly- sulfides [6], which are transformed into the desired colorless lith- ium alkanethiolate by addition of the stoichiometric amount of n butyllithium. Addition of 2-cyclohexen-1-one (1) to this solution leads to the formation of 3-(butylthio)cyclohexanone (2) in 50% isolated yield. However, if deoxygenated water, obtained by bubbling deoxygenated nitrogen under sonication, is added to 0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2008.06.014 * Corresponding author. Tel.: +55 11 3091 2176; fax: +55 11 3815 5579. E-mail address: jvcomass@iq.usp.br (J.V. Comasseto). Journal of Organometallic Chemistry 693 (2008) 2929–2936 Contents lists available at ScienceDirect Journal of Organometallic Chemistry journal homepage: www.elsevier.com/locate/jorganchem