26631-66-3Relevant academic research and scientific papers
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
Rossi, Renzo,Bellina, Fabio,Carpita, Adriano,Gori, Raffaele
, p. 381 - 392 (2007/10/02)
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.
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
Bellina, Fabio,Carpita, Adriano,Santis, Massimo De,Rossi, Renzo
, p. 12029 - 12046 (2007/10/02)
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.
Highly Regioselective Palladium-Mediated Synthesis of Stereoisomerically Pure (Z)- and (E)-Alkyl 2-Bromo-3-(hetero)arylpropenoates
Bellina, Fabio,Carpita, Adriano,Santis, Massimo De,Rossi, Renzo
, p. 6913 - 6916 (2007/10/02)
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
VERSATILE PRECURSORS FOR THE SYNTHESIS OF ENYNES AND ENEDIYNES
Myers, Andrew G.,Alauddin, Mian M.,Fuhry, Mary Ann M.,Dragovich, Peter S.,Finney, Nathaniel S.,Harrington, Philip M.
, p. 6997 - 7000 (2007/10/02)
(Z)-Ethyl 2,3-dibromopropenoate, readily available in multigram quantities, undergoes selective replacement of the β-bromide in coupling reactions with trimethylsilylacetylene to produce the (Z)-enyne 2.This product may be further elaborated to various fu
