The
mechanism of our previously reported catalytic asymmetric bromocyclization
reactions using 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl
(BINAP) monoxide was examined in detail by the means of control experiments,
NMR studies, X-ray structure analysis, and CryoSpray electrospray
ionization mass spectrometry (ESI-MS) analysis. The chiral BINAP monoxide
was transformed to a key catalyst precursor, proton-bridged bisphosphine
oxide complex (POHOP·Br), in the presence of N-bromosuccinimide (NBS) and contaminating water. The thus-formed
POHOP further reacts with NBS to afford BINAP dioxide and molecular
bromine (Br2) simultaneously in equimolar amounts. While
the resulting Br2 is activated by NBS to form a more reactive
brominating reagent (Br2NBS), BINAP dioxide serves
as a bifunctional catalyst, acting as both a Lewis base that reacts
with Br2NBS to form a chiral brominating agent
(PO+Br) and also as a Brønsted base
for the activation of the substrate. By taking advantage of this novel
concerted Lewis/Brønsted base catalysis by BINAP dioxide, we
achieved the first regio- and chemodivergent parallel kinetic resolutions (PKRs) of racemic unsymmetrical bisallylic
amides via bromocyclization.
Background: Japanese people are known to have the shortest sleep duration in the world. To date, no study has assessed a large Japanese population for insomnia and sleep duration. Methods: We performed an Ιnternet-based survey in association with a national television (TV) program. Questionnaire data were collected not only through personal computers, tablets, and smartphones, but also through the Hybridcast system, which combines broadcasts over airwaves with broadband data provided via the Internet using the TV remote controller. The Athens Insomnia Scale (AIS) was used to assess insomnia. Results: A total of 301,241 subjects participated in the survey. Participants slept for an average of 5.96 ± 1.13 h; the average AIS score was 6.82 ± 3.69. A total of 26.1% of male and 27.1% of female participants had both insomnia (AIS ≥ 6) and short sleep duration (<6 h). Responses were recorded through the Hybridcast system for 76.4% of the elderly (age ≥ 65 years) subjects and through personal computers, tablets, or smartphones for 59.9–82.7% of the younger subjects (age ≤ 65 years). Conclusions: Almost a quarter of the Japanese participants presented short sleep duration and insomnia. Furthermore, the Hybridcast system may be useful for performing large internet-based surveys, especially for elderly individuals.
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