We present the development of a method for the determination of methylene bridge crosslinking in ¹³C-labeled chloromethylated polystyrene-divinylbenzene resins. Our system uses a new room temperature reduction of the chloromethyl groups that circumvents the possible challenges associated with additional crosslinking. We demonstrate how the reduction of the chloromethyl groups allowed for the determination of methylene bridging, derived from the methylenebis(ethenylbenzene) crosslinker, based on the integration of the methylene signal in the ¹³C NMR spectra. Utilizing this method, the total crosslinking within the chloromethylated resin generated at 35 °C was determined to be upward of 10 wt %, which increased from 6 wt % in the unfunctionalized resin. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1955–1960

The synthesis of fully substituted carbon stereocenters remains a challenging task in organic chemistry. Recent developments in the design of substrates that undergo the Nazarov cyclization have enabled this reaction to become a valuable way to form elaborately substituted cyclopentane rings containing fully substituted carbon stereocenters. Three major strategies have been utilized in this endeavor. Here we provide an overview of these three areas that should give insight into the usage of the Nazarov reaction for the challenging task of forming fully substituted carbon stereocenters.

A molecular rearrangement of 5,5-spirocyclic cyclopentenones to 5,6-fused cyclopentenones catalyzed by Amberlyst^®15 is described. This work emphasizes the utility of renewable resources, such as furfural, that can be transformed into a variety of valuable products. It also highlights the viability of 5,5-spirocycles as intermediates en route to 5,6-fused cyclopentenones.