Effect of ester on rhodium-catalyzed intermolecular [5+2] cycloaddition of 3-acyloxy-1,4-enynes and alkynes.
نویسندگان
چکیده
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 terminal alkynes.
منابع مشابه
Rhodium-catalyzed carbonylation of 3-acyloxy-1,4-enynes for the synthesis of cyclopentenones.
Functionalized cyclopentenones were synthesized by a Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes, derived from alkynes and α,β-unsaturated aldehydes. The reaction involved a Saucy-Marbet 1,3-acyloxy migration of propargyl esters and a [4 + 1] cycloaddition of the resulting acyloxy substituted vinylallene with CO.
متن کاملRhodium-catalyzed 1,3-acyloxy migration and subsequent intramolecular [4+2] cycloaddition of vinylallene and unactivated alkyne.
A Rh-catalyzed 1,3-acyloxy migration of propargyl ester followed by intramolecular [4+2] cycloaddition of vinylallene and unactivated alkyne was developed. This tandem reaction provides access to bicyclic compounds containing a highly functionalized isotoluene or cyclohexenone structural motif, while only aromatic compounds were observed in related transition metal-catalyzed cycloadditions.
متن کاملRhodium-catalyzed 1,3-acyloxy migration and subsequent intramolecular [4+2] cycloaddition of vinylallene and unactivated alkynew
The Diels–Alder cycloaddition is arguably the most powerful reaction for the construction of substituted six-membered rings from various 2p and 4p reactants. However, unactivated 2p and 4p systems either require very harsh conditions or fail to undergo cycloadditions. In many cases, transition metal catalysts facilitated chemical transformations that were inaccessible under thermal conditions a...
متن کاملAll-Carbon [3+3] Oxidative Annulations of 1,3-Enynes by Rhodium(III)-Catalyzed C–H Functionalization and 1,4-Migration**
1,3-Enynes containing allylic hydrogens cis to the alkyne function as three-carbon components in rhodium(III)-catalyzed, all-carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl-to-allyl 1,4-rhodium(III) migration.
متن کاملRhodium-catalyzed linear codimerization and cycloaddition of ketenes with alkynes.
A novel rhodium-catalyzed linear codimerization of alkyl phenyl ketenes with internal alkynes to dienones and a novel synthesis of furans by an unusual cycloaddition of diaryl ketenes with internal alkynes have been developed. These reactions proceed smoothly with the same rhodium catalyst, RhCl(PPh(3))(3), and are highly dependent on the structure and reactivity of the starting ketenes.
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 49 26 شماره
صفحات -
تاریخ انتشار 2013