159721-59-2

Upstream product

• 59106-33-1 (Z)-ethyl 2-bromo-3-phenylprop-2-enoate 
• 7486-35-3 tri-n-butyl(vinyl)tin 
• 75-03-6 ethyl iodide 
• 873-66-5 1-propenylbenzene 
• 433733-19-8 2-benzyl-buta-2,3-dienoic acid ethyl ester 
• 10544-63-5 ethyl crotonate 
• 100-52-7 benzaldehyde 

Downstream Products

• 6285-99-0 (E)-benzylidenedihydro-2(3H)-furanone 
• 1093435-75-6 C₁₁H₁₂O 
• 852603-78-2 (E)-2-benzylidenebut-3-enal 

Relevant academic research and scientific papers

Asymmetric β,γ′-regioselective [4 + 3] and [4 + 2] annulations of α-vinylenals: Via cascade iminium ion-dienamine catalysis

Introduction of an α-vinyl group into enal substrates can prohibit the traditional [3 + 2] cycloaddition with N-2,2,2-trifluoroethyl isatin imines catalysed by a chiral secondary amine, but give β,γ′-regioselective [4 + 3] annulation products via cascade iminium ion-dienamine catalysis. A spectrum of CF3-containing spirooxindoles incorporating an azepane motif were constructed with good to excellent enantioselectivities. In addition, asymmetric [4 + 2] annulations between α-vinylenals and α,α-dicyanoalkenes were disclosed through a similar catalytic strategy, generally affording complex tricyclic frameworks with outstanding enantioselectivities.

Vinylogous Elimination/C-H Functionalization/Allylation Cascade Reaction of Allenoate Adducts: Synthesis of Ring-Fused Dihydropyridinones

A palladium-catalyzed cascade reaction of β′-allenoate adducts with aryl/heteroaryl carboxamides through a vinylogous elimination/C-H functionalization/intramolecular allylation reaction sequence has been developed with high Z stereoselectivity. Various ring-fused dihydropyridinones bearing an α,β-unsaturated ester substituent are obtained. It is the first example of application of the allenoate adducts to C-H functionalization annulations as practical precursors of hard-to-get functionalized electron-deficient 1,3-butadienes. Using air as the terminal oxidant also shows a great advantage in environmental friendliness.

Catalytic Cleavage of C(sp2)-C(sp2) Bonds with Rh-Carbynoids

We report a catalytic strategy that generates rhodium-carbynoids by selective diazo activation of designed carbyne sources. We found that rhodium-carbynoid species provoke C(sp2)-C(sp2) bond scission in alkenes by inserting a monovalent carbon unit between both sp2-hybridized carbons. This skeletal remodeling process accesses synthetically useful allyl cation intermediates that conduct to valuable allylic building blocks upon nucleophile attack. Our results rely on the formation of cyclopropyl-I(III) intermediates able to undergo electrocyclic ring-opening, following the Woodward-Hoffmann-DePuy rules.

ALKYL (E)- AND (Z)-2,3-DIBROMOPROPENOATES AS PRECURSORS TO 3-SUBSTITUTED ALKYL (E)- AND (Z)-2-BROMOPROPENOATES, 2,3-DISUBSTITUTED ALKYL (Z)- AND (E)-PROPENOATES AND SOME HETEROCYCLIC COMPOUNDS

3-(1-alkynyl)- and 3-aryl-substituted alkyl (Z)- and (E)-2-bromopropenoates have been stereospecifically and regioselectively synthesized by Pd-catalyzed cross-coupling reactions between 1-alkynylzinc chlorides, arylzinc chlorides or aryltributylstannanes and alkyl (Z)- and (E)-2,3-dibromopropenoates, (Z)- and (E)-2, respectively.The catalyst precursor consisting of a mixture of Pd on carbon and 3.9 equivalents of AsPh3 as well as that obtained by treatment of Pd(OAc)2 with 4 equivalents of AsPh3 in THF at 60 deg C can conveniently replace Pd(PPh3)4 in the reactions between (Z)- or (E)-2 and aryl or 1-alkynylzinc halides.On the other hand, a representative alkyl (Z)-3-alkyl-2-bromopropenoate has been prepared by reaction of a 9-alkyl-9-BBN derivative with (Z)-2a in DMF solution, in the presence of K2CO3 and a catalytic quantity of PdCl2(dppf).Some applications demonstrate the synthetic utility of 3-aryl-substituted alkyl (Z)- and (E)-propenoates, (Z)- and (E)-4.Thus, ethyl (E)-2-bromo-3-propenoate, (E)-4e, represents a direct precursor to 3-bromocoumarin, 7, and compound (Z)-8, which is obtained by acidic hydrolysis of (Z)-4e, undergoes a Pd-catalyzed intramolecular carbonylation reaction, which affords 3-ethoxycarbonylcoumarin, 9, in high yield.Moreover, treatment of compounds (Z)- and (E)-4 with organozinc or organotin derivatives, in the presence of catalytic amounts of a suitable Pd catalyst, affords, stereospecifically and in satisfactory to excellent yields, trisubstituted α,β-unsaturated esters, (E)- and (Z)-10, respectively, which cannot be easily prepared in stereoisomerically pure form by classical procedures.One of these esters, i.e. compound (E)-10c, represents a direct precursor to an isoaurone, i.e. (E)-3- benzylidenebenzofuran-2-one, (E)-11.Finally, a representative stereodefined unsymmetrically 2,3-diaryl-disubstituted alkyl propenoate has been synthesized by a one-pot procedure involving two sequential palladium-catalyzed arylations of (Z)-2a.

Highly Regioselective Palladium-Mediated Synthesis of Stereoisomerically Pure (Z)- and (E)-Alkyl 2-Bromo-3-(hetero)arylpropenoates

Stereoisomerically pure (Z)- and (E)-alkyl 2-bromo-3-(hetero)arylpropenoates, (Z)- and (E)-2, have been efficiently and selectively prepared by Pd(0)-mediated cross-coupling reaction between (hetero)arylzinc halides, 5, and easily available (Z)- and (E)-a

Synthesis of Variously 2-Substituted Alkyl (Z)- and (E)-2-Alkenoates and (Z)- and (E)-α-Ylidene-γ-butyrolactones via Palladium-Mediated Cross-Coupling Reactions between Organostannanes and Organic Halides

Stereoisomerically pure trisubstituted α,β-unsaturated ester of general formula 7 have been efficiently synthetized using two different protocols.The first one involves the palladium(0)/copper(I)-mediated cross-coupling reaction between alkyl (E)-2-tributylstannyl-2-alkenoates, (E)-2, and aryl or alkenyl iodides.The second protocol, which allows to prepare stereodefined 2-aryl, 2-methyl, 2-(1-alkenyl) as well as 2-acyl substituted α,β-unsaturated esters, is based on the cross-coupling reaction between easily available alkyl (Z)- or (E)-2-halo-2-alkenoates and organostannanes in NMP, in the presence of catalytic amounts of PdCl2(PhCN)2, AsPh3 and CuI. (Z)- and (E)-2-ethenyl substituted α,β-unsaturated esters prepared according to this procedure have been proven to be useful precursors to (Z)- and (E)-α-ylidene-γ-butyrolactones, (Z)- and (E)-8, respectively.