Synthesis of new organocatalysts having ortho-anilinyl-ethanol structure

Synthesis of new organocatalysts having ortho-anilinyl-ethanol structure Paolo Lupattelli,* Nadia Di Blasio, Lucia Chiummiento, Maria Funicello Department of Chemistry “Antonio Mario Tamburro”, University of Basilicata, v.le Ateneo Lucano 10, 85100 Potenza (Italy). email: paolo.lupattelli@unibas.it Increasing numbers of industrial applications are now based on asymmetric organocatalytic reactions, and the "green" aspect of this chemistry coupled with the catalysts’ sustainability, is widely considered for replacing reactions based on metal catalysis.1 Among the various activation methods, aminocatalysis relates to the particular reactivity of the nitrogen. For many years our research group has been concerned with the synthesis of 2,3-diaryloxiranes and their elaboration via regio- and stereoselective ring opening reactions, with the aim to afford, in a simple and immediate way, functionalized 1,2-diarylethanols.2 Recently a general regioselective reductive ring opening reaction was optimized and different enantiopure ortho-anilinyl-phenylethanols were prepared.3 By the use of suitable oxo-nucleophiles and acid catalysts, diastereoisomeric anilinyldiols were also obtained alternatively, in enantiospecific manner. Enantiopure aminoethers 1-2, and aminodiethers 3-4 were prepared starting from enantiopure trans epoxide 5 which were transformed into aminoalcohols 6, aminodiol 7 and dioxolane 8 by original procedure of regio- and stereoselective ring opening reactions. By selective alkylations of anilinyl alcohols recently optimized by our research group, compounds 7 and 8 were easily transformed into final products 1-3 with different substituents R1 and R2. Analogously, dioxolane 8 was elaborated using classical transacetalization reactions and reductions furnishing 4. Results of their efficiency in terms of acceleration and asymmetric induction in enantioselective organocatalytic reactions (aldol reactions, Michael additions, -heteroatom functionalizations of carbonyl) will also be presented. 1) (a) Dalko, P.I. Enantioselective Organocatalysis Wiley-VCH, 2007. (b) Blaser, H.U.; Pugin, B.; Spindler, F. J. Mol. Catal., Chemical 2005, 231, 1-20. (c) Thirsk, C.; Jay, D. Chem. Ind. 2004, 16, 15-17. 2) (a) Bonini, C.; Lupattelli, P. ARKIVOC, 2008, (viii), 150-182. (b) Solladié-Cavallo, A.; Lupattelli, P.; Bonini, C.; Ostuni, V.; Di Blasio, N. J. Org. Chem. 2006, 71, 9891. (c) Solladié-Cavallo, A.; Lupattelli, P.; Bonini, C. J. Org. Chem. 2005, 70, 1605. 3) Di Blasio, N.; Lopardo, M.T.; Lupattelli, P. Eur. J. Org. Chem. 2009, 938-944.