Graphene oxide, the oxidized form of graphite, is a common precursor to conductive nanosheets and used widely in the preparation of composite materials. GO has the benefits of easy exfoliation and handling, but it tends to aggregate and restack when reduced. One approach to overcoming this undesired aggregation is covalent modification of the nanosheets; however, this typically requires additional reagents and time. Herein, we report the simultaneous reduction and functionalization of graphene oxide using the Ritter reaction such that reduced nanosheets show good conductivity without the aggregation typical of unmodified material. GO reacts with nitriles in strongly acidic conditions to give highly reduced graphene oxide (C:O of 4.38:1) with covalently attached amides, which compatibilizes it to a number of organic solvents. This Ritter-type reaction produces carbocations on the basal plane of graphene oxide, which allows nucleophilic attack by the nitrogen of the nitrile and produces amides upon hydrolysis. The product has sheet resistance (57.60 ± 4.04 kΩ/sq) substantially lower than that of the starting graphene oxide (529.60 ± 10.04 kΩ/sq) and, more importantly, can easily be dispersed in various organic solvents and does not restack into graphite-like materials upon drying. This method yields individual conductive nanosheets that can be readily incorporated into a number of different systems.

The synthesis of 1-pyrrolines from N-alkenylnitrones and alkynes has been explored as ar etrosynthetic alternative to traditional approaches.T hese cascade reactions are formal [4 + 1] cycloadditions that proceed through ap roposed dipolar cycloaddition and N-alkenylisoxazoline [3,3']sigmatropic rearrangement. Av ariety of cyclic alkynes and terminal alkynes have been shown to undergo the transformation with N-alkenylnitrones under mild conditions to provide the corresponding spirocyclic and densely substituted 1-pyrrolines with high regio-and diastereoselectivity.M echanistic studies provide insight into the balance of steric and electronic effects that promote the cascade process and control the diastereo-and regioisomeric preferences of the 1-pyrroline products.D iastereoselective derivatization of the 1-pyrrolines prepared by the cascade reaction demonstrate the divergent synthetic utility of the new method.Scheme 1. N-Alkenylisoxazoline approach to 1-pyrroline synthesis.LG = leaving group. EWG = electron-withdrawing group.

The synthesis of 1-pyrrolines from N-alkenylnitrones and alkynes has been explored as ar etrosynthetic alternative to traditional approaches.T hese cascade reactions are formal [4 + 1] cycloadditions that proceed through ap roposed dipolar cycloaddition and N-alkenylisoxazoline [3,3']sigmatropic rearrangement. Av ariety of cyclic alkynes and terminal alkynes have been shown to undergo the transformation with N-alkenylnitrones under mild conditions to provide the corresponding spirocyclic and densely substituted 1-pyrrolines with high regio-and diastereoselectivity.M echanistic studies provide insight into the balance of steric and electronic effects that promote the cascade process and control the diastereo-and regioisomeric preferences of the 1-pyrroline products.D iastereoselective derivatization of the 1-pyrrolines prepared by the cascade reaction demonstrate the divergent synthetic utility of the new method.Scheme 1. N-Alkenylisoxazoline approach to 1-pyrroline synthesis.LG = leaving group. EWG = electron-withdrawing group.

The roles of substituent and solvent effects in promoting the 4π electrocyclization of N‐alkenylnitrones to give azetidine nitrones have been investigated by experimental examination of relative rates, activation energies, and linear free energy relationships. These transformations are synthetically important because they favor the formation of a strained heterocyclic ring with imbedded functionality and stereochemical information for versatile derivatization. Mechanistic investigations, including Hammett studies, solvent‐dependent Eyring studies, and solvent isotope effects, provide insight into the steric and electronic factors that control these electrocyclizations and identify trends that can be used to advance this approach towards the rapid synthesis of complex azetidines.

The roles of substituent and solvent effects in promoting the 4π-electrocyclization of N-alkenylnitrones to give azetidine nitrones have been investigated by experimental examination of relative rates, activation energies, and linear free energy relationships. These transformations are synthetically important because they favor formation of a strained heterocyclic ring with imbedded functionality and stereochemical information for versatile derivatization. Mechanistic investigations, including Hammett studies, solvent-dependent Eyring studies, and solvent isotope effects, provide insight into the steric and electronic factors that control these electrocyclizations and identify trends that can be used to advance this approach towards the rapid synthesis of complex azetidines.