An addition/cyclization reaction of 1,6-diynes was developed for the synthesis of highly substituted 1,2-dialkylidenecycloalkanes. In this work, 1,6-diynes reacted with (dimethylphenylsilyl)pinacol-borane in the presence of a palladium catalyst to afford 1,2-dialkylidenecycloalkanes bearing silyl and boryl groups with a (Z,Z)-configuration in good to excellent yields. Moreover, the corresponding products could be easily converted into other synthetically useful compounds. This protocol provides an efficient and practical method of heteroelement-element linkage addition to the unsaturated 1,6-diynes.
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http://dx.doi.org/10.1039/c8cc00097b | DOI Listing |
Chem Commun (Camb)
March 2018
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China. and Institute of Advanced Synthesis, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu 210009, China and Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637616, Singapore.
An addition/cyclization reaction of 1,6-diynes was developed for the synthesis of highly substituted 1,2-dialkylidenecycloalkanes. In this work, 1,6-diynes reacted with (dimethylphenylsilyl)pinacol-borane in the presence of a palladium catalyst to afford 1,2-dialkylidenecycloalkanes bearing silyl and boryl groups with a (Z,Z)-configuration in good to excellent yields. Moreover, the corresponding products could be easily converted into other synthetically useful compounds.
View Article and Find Full Text PDFJ Am Chem Soc
July 2012
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
The poly(quinoxaline-2,3-diyl)-based helically chiral phosphine ligands PQXphos exhibited high enantioselectivities up to 97% ee in palladium-catalyzed desymmetrization of meso-1,2-dialkylsubstituted-3-methylenecyclopropanes through silaborative cleavage of the C-C bond. The observed enantioselectivities were higher than those obtained with 2-diarylphosphino-1,1'-binaphthyl in our original report. Remarkable rate enhancement was also observed with a series of PQXphos in comparison with the corresponding low-molecular weight ligands.
View Article and Find Full Text PDFOrg Lett
July 2009
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.
Kinetic resolution of racemic 1-alkyl-2-methylenecyclopropanes via silaborative C-C cleavage was efficiently catalyzed by a palladium complex bearing a chiral phosphoramidite, affording 2-boryl-3-silylmethyl-1-alkenes as major products with up to 92% ee. Enantioenrichment through parallel kinetic resolution, where the slower reacting enantiomer was converted to the constitutional isomer of the major product, may be involved as the crucial stereodiscriminating step.
View Article and Find Full Text PDFJ Am Chem Soc
March 2007
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.
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