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Silaspiranes have attracted particular attention due to their chiral spiro-silicon center, which serves as an ideal carbon isostere and can endow spiro-analogs with distinct properties. Distinct from previously reported cyclization or cycloaddition strategies to form 5/5-silaspiranes, we report herein the asymmetric dual ring expansion of spirosilabicyclobutanes with alkynes to synthesize axially chiral spirosilabicyclohexenes bearing a novel 6/6-silaspirane framework. DFT (density functional theory) calculations provide the deep insight into the origin of the high enantioselectivity controlled by the sterically demanding binaphthyl phosphoramidite ligand. Preliminary studies of chiroptical properties indicate that one of the spirosilabicyclohexene analogs exhibit fluorescence emission, Cotton effects and CPL (circularly polarized luminescence) activity.

This article explores how geographic mobility is implicated in the process of bonding with place. By using data collected from a survey of a group of college graduates who grew up in Chaohu and left their hometown in their young adulthood, four types of migrants (Translocals, Departers, Aliens, and Settlers) and three types of returnees (the Trapped, the Bonded, and the Rooted) are classified. This research acknowledges the significance of traditional influences in people's bonds with places; meanwhile, it challenges the conservative view of seeing attachment/belonging to the homeland as universal and unconditioned. The findings also show that educated young migrants tend to have a greater desire to be integrated into the host city, and they are more prone to be accepted by the new socio-spatial environment. Taken together, this study corroborates the idea that geographic mobility does not undermine place-based attachment/belonging but tends to attenuate its intensity. Attachment/belonging is not necessarily limited to one single place; yet, attachment/belonging ascribed by birth still has an advantage over the attachment/belonging acquired by residence. Copyright © 2015 John Wiley & Sons, Ltd.