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Abstract Aromatic ring isosteres and rigidified saturated hydrocarbons are important motifs to enable drug discovery. Herein we disclose [2]-ladderanes as a class ofmeta-substituted aromatic ring isosteres and rigidified cyclohexanes. A straightforward synthesis of the building blocks is presented along with representative derivatization. Preliminary studies reveal that the [2]-ladderanes offer similar metabolic and physicochemical properties thus establishing this class of molecules as interesting motifs.more » « less
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Abstract Two catalytic systems have been developed for the arylboration of endocyclic enecarbamates to deliver synthetically versatile borylated saturated N‐heterocycles in good regio‐ and diastereoselectivities. A Cu/Pd dual catalytic reaction enables the synthesis of borylated, α‐arylated azetidines, while a Ni‐catalysed arylboration reaction efficiently functionalizes 5‐, 6‐, and 7‐membered enecarbamates. In the case of the Cu/Pd‐system, a remarkable additive effect was identified that allowed for broader scope. The products are synthetically useful, as demonstrated by manipulations of the boronic ester to access biologically active compounds.more » « less
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Abstract A new strategy for the synthesis of highly versatile cyclobutylboronates via the photosensitized [2+2]‐cycloaddition of alkenylboronates and alkenes is presented. The process is mechanistically different from other processes in that energy transfer occurs with the alkenylboronate as opposed to the other alkene. This strategy allows for the synthesis of an array of diverse cyclobutylboronates. The conversion of these adducts to other compounds as well as their utility in the synthesis of melicodenine C is demonstrated.more » « less
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Abstract A process to achieve 1,2‐metalate rearrangements of indole boronate as a way to access substituted indolines in high diastereoselectivities is presented. The reaction involves the generation of a Cu–allenylidene, which is sufficiently electrophilic to induce the 1,2‐metalate rearrangement. The scope of the reaction is evaluated as well as further transformations of the product.more » « less
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Abstract Double‐allylation reagents allow for the construction of highly complex molecules in an expedient fashion. We have developed an efficient, modular, and enantioselective approach towards accessing novel variants of these reagents through Cu/Pd‐catalyzed alkenylboration of alkenylboron derivatives. Importantly, we demonstrate novel use of an allylBdan reagent directly in a stereocontrolled allylation without initial deprotection to the boronic ester. These allylation products are employed in a second intermolecular allylation to access complex diol motifs, which has yet to be shown with these types of double‐allylation reagents. Overall, the modularity of this approach and the ease in which complex structural motifs can be accessed in a rapid manner signify the importance and utility of this method.more » « less
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A strategy for the photosensitized cycloaddition of alkenylboronates and allylic alcohols by a temporary coordination is presented. The process allows for the synthesis of a diverse range of cyclobutylboronates. Key to development of these reactions is the temporary coordination of the allylic alcohol to the Bpin unit. This not only allows for the reaction to proceed in an intramolecular manner but also allows for high levels of stereo and regiocontrol. A key aspect of these studies is the utility of the cycloadducts in the synthesis of complex natural products artochamin J and piperarborenine B.more » « less
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