Chemical engineers work across a number of sectors, processes differ within each of these areas, but chemistry and chemical engineering roles are found throughout, and are directly involved in the manufacturing process of chemical products and materials. Recommanded Product: 18-(tert-Butoxy)-18-oxooctadecanoic acid.
Theoretical Insights into Ester-Directed Reactions between Propiolates with 1,2-Benzisoxazoles by Au(I) Catalyst: [4+2]-Annulation versus Michael-Type Products
Au(I)-catalyzed selective reactions of Et- and Bu-t-substituted propiolates (1a and 1a’) with 1,2-benzisoxazole(2a) provide a new strategy for purposefully access to desired bioactive heterocycles. Using DFT calculations, we have systematically investigated the detailed mechanisms and origins of the ester-controlled chemoselectivity. The calculated results indicated that both reactions are initiated by LAu+ pi-coordination, N nucleophilic attack, and NTf2–assisted stepwise H-shift, generating a nitrilium species identified as a common and requisite intermediate, which is significantly different from the experimentally proposed 6-alkoxy-1,3-oxazin-1-ium intermediate. Starting from the nitrilium intermediate, the newly established nucleophilic cyclization, alkene release, and NTf2–assisted stepwise protodeauration provides [4 + 2]-annulation product P-1, while the nitrilum dissociation, O nucleophilic attack, and NTf2–assisted stepwise protodeauration generates Michael-type product P-2. Further explorations showed that Bu-t-controlled chemoselectivity of P-1 over P-2 can be attributed to the energy favorable aromaticity of selective-determining nucleophilic cyclization TS. With substitution of Bu-t by Et group, the reversal of chemoselectivity to P-2 formation might be closely related to the presence of extremely unstable Et cation in ethylene release TS leading to P-1.
Recommanded Product: 18-(tert-Butoxy)-18-oxooctadecanoic acid, Because enzymes can increase reaction rates by enormous factors and tend to be very specific, typically producing only a single product in quantitative yield, they are the focus of active research.you can also check out more blogs about 843666-40-0.
Reference:
Benzisoxazole – Wikipedia,
,Benzisoxazole – an overview | ScienceDirect Topics