Rhodium-catalyzed (E)-selective cross-dimerization of terminal alkynes.
نویسندگان
چکیده
Cross-dimerization of various terminal alkynes with different bulky terminal alkynes such as triisopropylsilylacetylene and 1-trimethylsilyloxy-1,1-diphenyl-2-propyne efficiently proceeds in the presence of a rhodium catalyst system to produce the corresponding (E)-enynes with high regio- and stereoselectivity.
منابع مشابه
gem-Selective Cross-Dimerization and Trimerization of Alkynes with Silylacetylenes Promoted by a Rhodium-Pyridine-N-Heterocyclic Carbene Catalyst
gem-Selective cross-dimerization and trimerization of silylacetylenes with alkynes via C-H activation using a rhodium(I)-pyridine-Nheterocyclic carbene catalyst have been developed. This protocol is applicable to variety of aliphatic or aromatic terminal alkynes, internal alkynes and gem-1,3-disubsituted enynes to afford the corresponding enynes and dienynes with high regioand stereoselectiviti...
متن کاملPyridine-enhanced head-to-tail dimerization of terminal alkynes by a rhodium-N-heterocyclic-carbene catalyst.
A general regioselective rhodium-catalyzed head-to-tail dimerization of terminal alkynes is presented. The presence of a pyridine ligand (py) in a Rh-N-heterocyclic-carbene (NHC) catalytic system not only dramatically switches the chemoselectivity from alkyne cyclotrimerization to dimerization but also enhances the catalytic activity. Several intermediates have been detected in the catalytic pr...
متن کاملMild and selective palladium-catalyzed dimerization of terminal alkynes to form symmetrical (Z,Z)-1,4-dihalo-1,3-dienes.
A regioselective and stereoselective palladium-catalyzed dimerization of terminal alkynes method for the synthesis of symmetrical (Z,Z)-1,4-dihalo-1,3-dienes is presented. In the presence of a catalytic amount of PdX(2) and 3 equiv of CuX(2) (X = Cl and Br), terminal alkynes were dimerized to afford (Z,Z)-1,4-dihalo-1,3-dienes in good yields. The results showed that the effect of solvent had a ...
متن کاملEffect of ester on rhodium-catalyzed intermolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes and alkynes.
We systematically examined the effect of different esters on the rhodium-catalyzed intermolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes and alkynes with a concomitant 1,2-acyloxy migration. Significant rate acceleration was observed for benzoate substrates bearing an electron-donating substituent. The cycloaddition can now be conducted under much more practical conditions for most termina...
متن کاملReactivity and Chemoselectivity of Allenes in Rh(I)-Catalyzed Intermolecular (5 + 2) Cycloadditions with Vinylcyclopropanes: Allene-Mediated Rhodacycle Formation Can Poison Rh(I)-Catalyzed Cycloadditions
Allenes are important 2π building blocks in organic synthesis and engage as 2-carbon components in many metal-catalyzed reactions. Wender and co-workers discovered that methyl substituents on the terminal allene double bond counterintuitively change the reactivities of allenes in [Rh(CO)2Cl]2-catalyzed intermolecular (5 + 2) cycloadditions with vinylcyclopropanes (VCPs). More sterically encumbe...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemical communications
دوره 29 شماره
صفحات -
تاریخ انتشار 2008