Internal migration

A deuterium-labeling study of a reaction of this type demonstrated syn stereoselectivity in both the oxypalladation and P-elimination, which indicates that the cyclization occurs by internal migration, rather than by an anti nucleophilic capture.113 This particular system also gives products from double-bond migration that occurs by reversible Pd(II)-D addition-elimination. 

The biradical reacts unimolecularly in several ways (a) it is converted to hot epoxide by ring closure, (b) it rearranges by internal migration of H atoms or alkyl groups into hot carbonyl compounds, (c) it decomposes ( pressure-independent fragmentation occurs—the biradical is too short-lived to undergo collisional stabilization). 

On the other hand, in a similar study recently carried out by Falconer et al. (41), no evidence was found for the presence of allyl radicals and the occurrence of reaction (23) appears unlikely. The products could be explained by assuming initial formation of hot iso- and n-propyl radicals. As will be discussed in the next section, 94% of iso- and 6% of propyl radicals are formed in this reaction. The further fate of both these radicals has to be considered, since hot n-propyl decomposes readily into C2H4 and CH3 but the same is not true for iso-propyl, where a simultaneous internal migration of an H atom must occur. 

Schmunis, G. A. (2007). Epidemiology of Chagas disease in non-endemic countries The role of international migration. Mem. Inst. Oswaldo Cruz 102(Suppl. I), 75-85. 

Elegant labeling studies by Denmark, summarized in Scheme 5.2.1, showed that the infia-molecular thermal allylation from 4 exclusively provides the corresponding E-isomer of 6 via a syn-SE reaction, indicative of the internal C O transfer of the stannyl residue. Keck also reported the formation of 18 by thermolysis of Z-16 (Scheme 5.2.3). However, in this study the thermal cyclization of isomeric E-19 yielded largely axial alcohol 21, which cannot be rationalized through an internal migration of tin to the carbonyl oxygen. 

Available surface active may be limited by external leaching or by internal migration within the plastic... 

The Colombian conflict occurs within a context of economic crisis, underdevelopment, unemployment, poverty, an increasing level of informal and illegal economic activities, internal migrations, and a strong state legitimacy crisis caused by the state impossibility to grant the rule of law and the weakness of political institutions. 

Raymer, J. and Willekens, F. International Migration in Europe Data, Models and Estimates. John Wiley Sons, Ltd, Chichester, UK, 2008. 

When the formed monoglycerides are analyzed by periodie acid oxidation, however, the fatty acids are not found exclusively in the 2-position 10-20% of the isomers are 1-monoglycerides. Therefore either lipase is not completely specifie for 1 and 3 positions, or internal migration of the fatty acids occurs (237). 

As noted in Chapter 11, the cis products are thought to form by external attack of acetate on a coordinated diene, followed by external attack of the second carboxylate on the intermediate allyl species. The trans products are thought to form by external attack of one nucleophile to a coordinated diene and subsequent internal migration of the second nucleophile from the metal to the resulting allyl intermediate. These reaction mechanisms, including the coordination by benzoquinone to the intermediate to induce elimination, are shown in Scheme 16.26. 

Zubaran, C., The international migration of healthcare professionals, Australas Psychiatry Dec 20(6) 512-517,2012. 

In the case of very wide gradation, the situation requires an additional check with respect to the internal migration. In this respect, an important parameter is the so-called uniformity coefficient C , defined by Eq. (19.13) and the shape of the... 

The binding of the nucleophile to the boron atom in structure 5 facilitates the internal migration and nucleophilic displacement with inversion to the point that side reactions such as P-elimination are not observed. Strongly basic nucleophiles work best in the conversion of 4 into 7, but the displacement process is assisted by the boron atom even if a fiilly covalent bond to boron is probably not involved [9j. 

Evidence for a hydride internal migration also was presented in the reaction of (C2H4PdCl2)2 with deuterium oxide, which gave acetaldehyde free from deuterium. This indicates that vinyl alcohol was not a reaction intermediate. The lack of exchange is also consistent with a direct 1,2-hydride shift. 

Birks, J. S., Sinclair, C. (1980). International migration and development in the Arab region. Geneva International Labour Office. 

Oliver Bake we 11 is Co-Director of the International Migration Institute at the University of Oxford. 

Jerome Elie is an independent historian and consultant on international migration and refugee issues. 

Susan F. Martin holds the Donald G. Herzberg Chair in International Migration and is the Director of the Institute for the Study of International Migration in the School of Foreign Service at Georgetown University. 

Black, R.(2001) Fifty Years ofRefugee Studies From Theory to Policy. International Migration Review 35(1) 57-78. 

Adamson, F. B. (2006) Crossing Borders International Migration and National Security. International Security 31(1) 165-99. 

Veitovec, S. (2004) Migrant Transnationalism and Modes of Transformation. International Migration Review 38(3) 970-1001. 

Weiner, M. (1993) International Migration and Security. Boulder, CO Westview Press. 

Ganuneltoft-Hansen, T., and Sorensen, N. N. (eds.) (2013) The Migration Industry and the Commercialization of International Migration. London Roufledge. 

Richmond, A. H. (1988) Sociological Theories of International Migration The Case of Refugees. Current Sociology 36(2) 7-25. 

Sorensen, N. N., Van Hear, N., and Engberg-Pedersen, P. (2002) The Migration-Development Nexus Evidence and Policy Options. International Migration 40(5) 3-47. 

Connor, P., and Massey, D. S. (2010) Economic Outcomes among Latino Migrants to Spain and the United States Differences by Source Region and Legal Status. International Migration Review 44(4) 802-29. 

Rogge, J. R. (1981) Africa s Resetdement Strategies. International Migration Review 15(1/2) 195-212. 

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