52 research outputs found
Nickel-Catalyzed CarbonâCarbon Bond-Forming Reactions of Unactivated Tertiary Alkyl Halides: Suzuki Arylations
The first Suzuki cross-couplings of unactivated tertiary alkyl electrophiles are described. The method employs a readily accessible catalyst (NiBr[subscript 2]¡diglyme/4,4â˛-di-tert-butyl-2,2â˛-bipyridine, both commercially available) and represents the initial example of the use of a group 10 catalyst to cross-couple unactivated tertiary electrophiles to form CâC bonds. This approach to the synthesis of all-carbon quaternary carbon centers does not suffer from isomerization of the alkyl group, in contrast with the umpolung strategy for this bond construction (cross-coupling of a tertiary alkylmetal with an aryl electrophile). Preliminary mechanistic studies are consistent with the generation of a radical intermediate along the reaction pathway.National Institute of General Medical Sciences (U.S.) (R01-GM62871)Merck Research Laboratories (Summer Fellowship
Trajectories of Early Adolescent Loneliness: Implications for Physical Health and Sleep
The current study examines the relationship between prolonged loneliness, physical health, and sleep among young adolescents (10â13 years; Nâ=â1214; 53% girls). Loneliness was measured at 10, 12 and 13 years of age along with parent-reported health and sleep outcomes. Using growth mixture modelling, 6 distinct trajectories were identified: âlow increasing to high lonelinessâ (nâ=â23, 2%), âhigh reducing lonelinessâ (nâ=â28, 3%), âmedium stable lonelinessâ (nâ=â60, 5%), âmedium reducing lonelinessâ (nâ=â185, 15%), âlow increasing to medium lonelinessâ (nâ=â165, 14%), and âlow stable lonelinessâ (nâ=â743, 61%). Further analyses found non-significant differences between the loneliness trajectories and parent-report health and sleep outcomes including visits to health professionals, perceived general health, and sleep quality. The current study offers an important contribution to the literature on loneliness and health. Results show that the relationship may not be evident in early adolescence when parent reports of childrenâs health are used. The current study highlights the importance of informant choice when reporting health. The implications of the findings for future empirical work are discussed
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