A highly selective cascade reaction that allows the direct transformation of dienallenes to spirocyclobutenes (spiro[3.4]octenes) as single isomers has been developed. The reaction involves formation of overall four C-C bonds and proceeds via a palladium-catalyzed oxidative transformation with insertion of olefin, olefin, and carbon monoxide. Under slightly… (More)
An efficient one-pot method for the enzyme- and ruthenium-catalyzed enantioselective transformation of α-allenic alcohols into 2,3-dihydrofurans has been developed. The method involves an enzymatic kinetic resolution and a subsequent ruthenium-catalyzed cycloisomerization, which provides 2,3-dihydrofurans with excellent enantioselectivity (up to >99 % ee).… (More)
A highly efficient palladium-catalyzed oxidative borylation of enallenes was developed for the selective formation of cyclobutene derivatives and fully-substituted alkenylboron compounds. Cyclobutenes are formed as the exclusive products in MeOH in the presence of H2 O and Et3 N, whereas the use of AcOH leads to alkenylboron compounds. Both reactions showed… (More)
We report a palladium-catalyzed oxidative functionalization of alkynes to generate α-acetoxylated enones in one step. A range of functional groups are well-tolerated in this reaction. Mechanistic studies, including the use of (18) O-labeled DMSO, revealed that the ketone oxygen atom in the product originates from DMSO.
An efficient copper-mediated three-component reaction of 2,3-allenoates or 2-alkynoates, amines, and nitriles affording fully substituted pyrazoles with a very nice diversity has been developed. A tandem conjugate addition, 1,2-addition, and N-N bond formation mechanism has been proposed for this diverse synthesis of pyrazoles based on mechanistic studies.
As a building block of analog-to-digital converter (ADC), comparator plays an important role, especially the case latched comparator for super-high speed ADC. The speed and performance of latched comparator mostly decide the performance of the whole ADC. In this paper, a multi-stage purely dynamic high speed latched comparator for folding and interpolating… (More)