O presente trabalho é referente ao estudo das indústrias líticas do sítio Brito, localizado na margem direita do rio Paranapanema, no Estado de São Paulo. Os materiais estudados estão associados a datações recuadas a transição Holoceno Inicial/Médio, entre, aproximadamente, 8.000 BP e 6.500 BP. O nosso primeiro objetivo concerne à caracterização tecnológica das indústrias líticas a partir de uma abordagem centrada no conceito de cadeia operatória visando reconstituir os processos técnicos e as estratégias de uso das matérias primas que geraram a variabilidade artefatual observada. O segundo objetivo trata da verificação, por meio da análise da distribuição vertical e horizontal dos vestígios, da integridade de solos de ocupação identificados durante a escavação. Propomos que as indústrias líticas mais antigas do sítio Brito estão distribuídas em um nível arqueológico caracterizado por um palimpsesto de ocupações. / The present dissertation refers to the study of the lithic assemblages from the Brito site, located at the right bank of the Paranapanema river, in the state of São Paulo. The materials that were studied are associated to dates that go back to the transition between the initial and the middle Holocene, approximately 8,000 to 6,500 BP. Our first objective concerns the technological characterization of the lithic assemblages from an approach based on the concept of operation sequence (chaîne opératoire), with the aim of reconstituting the technical processes and the strategies of usage of raw material that generated the observed artifact variability. The second objective was to verify, by means of analyzing the vertical and horizontal distribution of the lithic materials, the integrity of the occupational floors identified during the fieldwork. We suggest that the oldest lithic assemblages of the Brito site are distributed over an archeological level characterized by a palimpsest of occupations.

O presente trabalho é referente ao estudo das indústrias líticas do sítio Brito, localizado na margem direita do rio Paranapanema, no Estado de São Paulo. Os materiais estudados estão associados a datações recuadas a transição Holoceno Inicial/Médio, entre, aproximadamente, 8.000 BP e 6.500 BP. O nosso primeiro objetivo concerne à caracterização tecnológica das indústrias líticas a partir de uma abordagem centrada no conceito de cadeia operatória visando reconstituir os processos técnicos e as estratégias de uso das matérias primas que geraram a variabilidade artefatual observada. O segundo objetivo trata da verificação, por meio da análise da distribuição vertical e horizontal dos vestígios, da integridade de solos de ocupação identificados durante a escavação. Propomos que as indústrias líticas mais antigas do sítio Brito estão distribuídas em um nível arqueológico caracterizado por um palimpsesto de ocupações. / The present dissertation refers to the study of the lithic assemblages from the Brito site, located at the right bank of the Paranapanema river, in the state of São Paulo. The materials that were studied are associated to dates that go back to the transition between the initial and the middle Holocene, approximately 8,000 to 6,500 BP. Our first objective concerns the technological characterization of the lithic assemblages from an approach based on the concept of operation sequence (chaîne opératoire), with the aim of reconstituting the technical processes and the strategies of usage of raw material that generated the observed artifact variability. The second objective was to verify, by means of analyzing the vertical and horizontal distribution of the lithic materials, the integrity of the occupational floors identified during the fieldwork. We suggest that the oldest lithic assemblages of the Brito site are distributed over an archeological level characterized by a palimpsest of occupations.

Nous effectué des réactions de cyclisations [3 +2] énantiosélectives entre des allénoates et des énones, catalyseées par des phosphines, donnant accès à des hétérocycles soufrés présentant des motifs moléculaires spirocycliques porteurs de nombreux centres asymétriques. De bons rendements chimiques et des bon excès énantiomériques ont été obtenus en utilisant le (S,S)-FerroPHANE comme le catalyseur chiral.D’autre part, nous avons développé de nouvelles réactions catalysées par les phosphines donnant accès à des hétérocycles azotés. En tenant de la réactivité des phosphines connue dans la Littérature, nous avons envisagé des substrats permettant la combinaison de différents processus catalytique.Des réactions de cyclisation [3+2], catalysées par les phosphines, entre des imines et des diènes conjugués, doublement activés à leurs extrémités, permet d’accéder en une seule étape à des 3-pyrrolines tri-substituées de manière diastéréosélective. Nous avons alors évalué les possibilités et limitation de cette nouvelle voie d’accès aux pyrrolines en mettant en jeu de toute une gamme de diènes et d’imines diversement fonctionnalisés.Nous avons ensuite étudié ce nouveau mode de cyclisation en utilisant des diènes où l’une des deux insaturations est inscrite dans un cycle. Dans le cas de ces substrats cycliques, des composés portant le motif hexahydroisoindol-4-one ont été obtenus de manière très efficace.Enfin, il a été montré que des diènes portant le motif coumarine réagissaient avec des imines en présence de quantités stœchiométriques de phosphine et d'eau pour donner lieu à un processus domino sans précédent: une réaction de aza-Morita-Baylis Hillman suivi d’une réaction de réduction. Ce processus s'est avéré très chimiosélectif et procède avec un excellent contrôle des configurations relatives des deux centres asymétriques contigus nouvellement formés.L’ensemble de ces études ont permis de mettre en valeur l’efficacité de la catalyse par les phosphines nucléophiles pour la formation d’hétérocycles soufrés et azotés, structurellement diversifiés et hautement fonctionnalisés, à partir de matières premières facilement accessibles. / We have applied the enantioselective [3+2] cyclisations between allenoates and enones, under phosphine catalysis, to the asymmetric synthesis of sulfides and sulfoxides displaying unprecedented spirocyclic molecular scaffolds and multiple stereocentres. Notably, good yields and e.e’s were obtained by using (S,S)-FerroPHANE as the chiral catalyst. Then, we established a highly diastereoselective oxidation procedure which converts the enantiomerically enriched spirocyclic sulfides into the corresponding sulfoxides. On the other hand, we have developed new phosphine promoted reactions for the synthesis of nitrogen heterocycles. From the known modes of action of phosphine nucleophiles, we have designed new combinations of properly functionalized substrates that have been processed in the presence of phosphorus catalysts. The [3+2] annulation reaction between imines and acyclic conjugated dienes, properly activated by electron withdrawing groups on both ends, affords a new efficient and diastereoselective approach to functionalized 3-pyrrolines, under phosphine catalysis. We have studied the scope and limitations of this strategy by considering a whole range of differently substituted dienes and imines. As an extension, we have also considered analogous cyclizations between imines and cyclic conjugated dienes in which one of the double bonds is embedded in a cyclic moiety which afforded the functionalized hexahydroisoindol-4-one derivatives. Coumarin derived dienes reacted however with stoichiometric amounts of phosphine and water to give an unprecedented domino process, i.e. a formal aza-Baylis Hillman-reduction sequence. The process proved to be highly chemoselective and allowed an excellent stereochemical control of the relative configurations of two, newly created, contiguous carbon centres.These studies have demonstrated that the phosphine catalysis affords simple and efficient methodologies for the synthesis of structurally diverse and highly functionalized heterocycles, starting from easily available starting materials

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