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Dedicated on the occasion of his 75th birthday to Professor Günther Wilke, an outstanding pioneer in transition metal catalyzed organic synthesisA comparative mechanistic study of the nickel(0)-catalyzed homo-oligomerization and co-oligomerization of alkynes and of nitriles has been undertaken, with diphenylacetylene and benzonitrile, towards an array of nickel(0) reagents, such as finely divided nickel, (COD) 2 Ni, (Bpy)(COD)Ni, (Et 3 P) 4 Ni, (Bpy)(PhCϵCPh)Ni and (COD) 2 Ni−MeAlCl 2 combinations in donor (THF) and nondonor (PhMe or neat substrate) solvents. Special attention has been given to the detailed molecular structures of the initial 1:1 adducts, (Bpy)(PhCϵCPh)Ni, (Ph 3 P) 3 (PhCϵCPh)Ni and [(Ph 3 P)(PhCϵN)Ni] 4 by a consideration of XRD and IR data. Data from the single crystal XRD analysis of (Bpy)(PhCϵCPh)Ni, reported here for the first time, are shown to be in excellent accord with the presence of a 2,3-diphenylnickelacyclopropene ring for the (PhCϵCPh)Ni moiety with almost coplanar chelating coordination of the bipyridyl ligand, rather than with the presence of simple ''side-on'' coordination of the alkyne with the metal center. A parallel analysis of XRD and IR data for the two benzonitrile-nickel(0) complexes, which were drawn from previous publications, has concluded that the nickel in (Ph 3 P) 3 (PhCϵN)Ni is coordinated in an ''end-on'' fashion and the nickel centers in [(Ph 3 P)(PhCϵN)Ni] 4 are coordinated as bridges between nitrile units in both an ''end-on'' and ''sideon'' manner. The stereochemistry of the acid hydrolysis of the

Dialkyltitanium(IV) derivatives, R 2 TiE 2 , where E ) X, OR, react with unsaturated organic substrates, such as olefins, acetylenes, azoarenes, aldehydes, ketones, and imines, to undergo in high yield epimetalation with TiE 2 by transfer. In a general fashion, this finding now permits the stoichiometric generation of these threemembered titanacycles from diverse unsaturated substrates and their transformation into useful, metal-free derivatives by protolysis/deuteriolysis, oxidation, or unsaturated monomer insertion at the C-Ti bond.The oxidative addition of subvalent transition-metal reagents (M t n L m , 1) to various CdC, CtC, CdO, or Cd N linkages (as in 2), with the formation of threemembered metallacycles, has been termed epimetalation (eq 1). 2 The bonding character of the metallacyclic adduct can range from a metallacycloprop(en)yl ring (3) having two σ-like C-M t bonds and a higher oxidation number for the metal center, M t n+2 , to a π complex (4) having little change in the M t n oxidation number. Assigning the relative importance of resonance structures 3 and 4 requires careful evaluation of the structural parameters of the individual adduct, if isolated, or of its observed chemical reactions. 2-4 The intermediacy of such metallacycles containing titanium has been postulated for a number of unusual, recently reported reactions: 5 (1) the Kulinkovich synthesis of cyclopropanols from ethyl Grignard reactions with esters catalyzed by Ti(OPr i ) 4 , 6 (2) the de Meijere modification of the Kulinkovich synthesis, whereby (dialkylamino)cyclopropanes result from the interaction of dialkylamides and alkyl Grignard reagents catalyzed by Ti(OPr i ) 4 , 7 (3) the Sato modification of the Kulinkovich reaction, in which the coupling of acetylenes and aldehydes, ketones, or imines is promoted by stoichiometric amounts of Ti(OPr i ) 2 , 8 and (4) our stereoselective, stoichiometric coupling of carbonyl derivatives to pinacols or to olefins and the catalytic cyclotrimerization of acetylenes to benzene derivatives, both effected by TiCl 2 . 2,9 In all such situations it has been assumed that the requisite titanium(II) reagent (8 or 9) has been generated by the alkylative reduction of TiE 4 (5) and the subsequent, spontaneous reductive elimination of the two R groups as alkene and alkane from R 2 TiE 2 For an overview of the Kulinkovich reaction for organic synthesis: Breit, B. J. Prakt. Chem. 2000, 342 and the more extensive reviews of Kulinkovich and de Meijere 6c and of Sato, Urabe, and Okamoto. 7c (6) (a) Kulinkovich, O. G.; Sviridov, S. V.; Vasilevski, D. A.; Prityckaja, T. S. de Meijere, A.; Williams, C. A.; Kourdioukov, A.; Sviridov, S. V.; Chaplinski, V.; Kordes, M.; Savachenko, A. I.; Stratmann, C.; Noltemeyer, M. Chem. Eur.

An investigation of the Kulinkovich cyclopropanol synthesis, the interaction of esters with 2:1 or 3:1 mixtures of alkyl Grignard reagents and Ti(OiPr) 4 at low temperatures, has been conducted, in order to ascertain which reactive intermediates are involved and how they are interconverted. Because of the nature of the ultimate product, one of the most obvious intermediates is the 1,1-diisopropoxy-1-titanacyclopropane stemming from the epititanation of the alkene set free from the alkyl Grignard reagent employed. A search for the formation of such a titanocycle by warming an ethereal solution of either Et 2 Ti(OiPr) 2 or iPr 2 Ti(OiPr) 2 between −78°C and +25°C was attempted by chemical trapping with either an ester or nitrile. In this manner it was shown that such a titanocycle was formed in the case of Et 2 Ti(OiPr) 2 but not with iPr 2 Ti(OiPr) 2 . As to the role of two other potential intermediates, Ti(OiPr) 2 and R 2 Ti(OiPr) 2 , it was demonstrated that preformed Ti(OiPr) 2 in the presence of ethylene and an ester does not form the corresponding cyclopropanol. Thus, under the reaction conditions Ti(OiPr) 2 cannot perform the direct epimetallation necessary to produce the requisite titanacy-

BackgroundServing on volunteer groups undertaking medical mission trips is a common activity for health care professionals and students. Although volunteers hope such work will assist underserved populations, medical mission groups have been criticized for not providing sustainable health services that focus on underlying health problems. As members of a volunteer medical mission group, we performed a bed net indicator study in rural Mali. We undertook this project to demonstrate that volunteers are capable of undertaking small-scale research, the results of which offer locally relevant results useful for disease prevention programs. The results of such projects are potentially sustainable beyond the duration of a mission trip.MethodsVolunteers with Medicine for Mali interviewed 108 households in Nana Kenieba, Mali during a routine two-week medical mission trip. Interviewees were asked structured questions about family demographics, use of insecticide treated bed nets the previous evening, as well as about benefits of net use and knowledge of malaria. Survey results were analyzed using logistic regression.ResultsWe found that 43.7% of households had any family member sleep under a bed net the previous evening. Eighty seven percent of households owned at least one ITN and the average household owned 1.95 nets. The regression model showed that paying for a net was significantly correlated with its use, while low perceived mosquito density, obtaining the net from the public sector and more than four years of education in the male head of the household were negatively correlated with net use. These results differ from national Malian data and peer-reviewed studies of bed net use.ConclusionsWe completed a bed net study that provided results that were specific to our service area. Since these results were dissimilar to peer-reviewed literature and Malian national level data on bed net use, the results will be useful to develop locally specific teaching materials on malaria prevention. This preventive focus is potentially more sustainable than clinical services for malaria treatment. Although we were not able to demonstrate that our work is sustainable, our study shows that volunteer groups are capable of undertaking research that is relevant to their service area.