Highly diastereroselective synthesis of dihydrofurans and dihydropyrroles via pyridine catalyzed formal [4+1] annulation.
نویسندگان
چکیده
A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.
منابع مشابه
Highly enantioselective syntheses of homopropargylic alcohols and dihydrofurans catalyzed by a bis(oxazolinyl)pyridine-scandium triflate complex.
Lewis acid promoted reactions of allylsilanes and allenylsilanes provide access to important building blocks for natural product synthesis.1 For example, trimethylsilylallenes function as propargylic anion equivalents in aldehyde addition reactions (eq 1, Path A).2 If the silicon center is sterically congested, the normal addition pathway is suppressed and functionalized dihydrofurans are produ...
متن کاملP(NMe2)3-mediated reductive [1+4] annulation of isatins with enones: a facile synthesis of spirooxindole-dihydrofurans.
A novel P(NMe2)3-mediated reductive [1+4] annulation reaction between isatins and enones has been developed, providing the facile synthesis of spirooxindole-dihydrofurans. This reaction unveils the first practical approach to construct five-membered cyclic motifs via a Kukhtin-Ramirez adduct involved [1+4] annulation mode.
متن کاملPractical Pd(TFA)2-Catalyzed Aerobic [4+1] Annulation for the Synthesis of Pyrroles via “One-Pot” Cascade Reactions
The Pd(TFA)2-catalyzed [4+1] annulation of chained or cyclic α-alkenyl-dicarbonyl compounds and unprotected primary amines for “one-pot” synthesis of pyrroles is reported here. Enamination and amino-alkene were involved in this practical and efficient tandem reaction. The annulation products were isolated in moderate to excellent yields with O2 as the terminal oxidant under mild conditions. In ...
متن کاملSynthesis of azepines by a gold-catalyzed intermolecular [4 + 3]-annulation.
A convenient gold(III)-catalyzed synthesis of azepines from the intermolecular annulation of propargyl esters and alpha,beta-unsaturated imines is reported (19 examples, 55-95% yield). This formal [4 + 3]-cycloaddition reaction is proposed to proceed via a stepwise process involving intramolecular trapping of an allyl-gold intermediate.
متن کاملPhosphine-catalyzed [3 + 2] cycloaddition of allenoates with trifluoromethylketones: synthesis of dihydrofurans and tetrahydrofurans.
The triphenylphosphine-catalyzed formal [3 + 2] cycloaddition of allenoates and trifluoromethylketones was realized to give the corresponding dihydrofurans in good yields with excellent γ-regioselectivities. Hydrogenation of the dihydrofurans gave 2,4,4-trisubstituted tetrahydrofurans in good yields with exclusive cis-selectivities.
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 47 4 شماره
صفحات -
تاریخ انتشار 2011