There have been significant advancements in radical-mediated reactions through covalent-based organocatalysis. Here, we present the generation of iminyl and amidyl radicals via N-heterocyclic carbene (NHC) catalysis, enabling diastereoselective aminoacylation of trisubstituted alkenes. Different from photoredox catalysis, single electron transfer from the deprotonated Breslow intermediate to O-aryl hydroxylamine generates an NHC-bound ketyl radical, which undergoes diastereocontrolled cross-coupling with the prochiral C-centered radical. This operationally simple method provides a straightforward access to a variety of pyrroline and oxazolidinone heterocycles with vicinal stereocenters (77 examples, up to >19:1 d.r.). Electrochemical studies of the acyl thiazolium salts support our reaction design and highlight the reducing ability of Breslow-type derivatives. A detailed computational analysis of this organocatalytic system suggests that radical−radical coupling is the rate-determining step, in which π−π stacking interaction between the radical intermediates subtly controls the diastereoselectivity.

Non-work trips have increased remarkably over recent years, even exceeding the amount of daily work-related trips. It is therefore important to understand the relationship between the non-work trip frequency and accessibility of the travelers. However, the conclusions of previous studies were inconsistent. The causes of this inconsistency have been speculated to be the limitations of sample size, aggregated accessibility, and home-based trips. To explore the actual relationships between the non-work trip frequency and accessibility, this study employs a more reliable method based on mobile phone data. First, positioning data of mobile phone users was used to identify activity points, home and workplace locations, and non-work trips of the users. Furthermore, the socioeconomic attributes and preferences of users were extracted from mobile phone user feature data. Second, accessibility was measured at the individual level based on a real-time travel-cost estimation method. Subsequently, the negative binomial regression model was employed to study the effects of accessibility, socioeconomic attributes, and preferences of users on their travel frequencies. A case study of the central business district of Lujiazui in Shanghai was conducted to prove the feasibility of the proposed method. The results show that the non-work trip frequency increases with accessibility. Moreover, users with higher consumption levels are more sensitive to accessibility when they decide the frequency of the non-work trips. However, the influence of accessibility on non-work trip frequency tends to weaken with the decrease of accessibility. These findings contribute to a more reliable transportation policy design and planning.

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