Vinylic Selenides and Tellurides - Preparation, Reactivity and Synthetic Applications

Clean and atom-economic synthesis of alpha-phenylselenoacrylonitriles and alpha-phenylseleno- alpha,beta-unsaturated esters by knoevenagel reaction under solvent-free conditions

“…1 Among the different classes of organoselenium compounds, vinyl selenides constitute a very useful intermediate, because the versatile reactivities of the selanyl group and the carbon-carbon double bond. 2 Special attention has been devoted to the synthesis of vinyl selenides substituted by electron-withdrawing groups, like nitriles 3 and esters 4. These highly functionalized compounds can be submitted to several transformations, including their use in [2+2] cycloaddition reactions, 3 Diels-Alder reactions, [4][5][6] and like Michael acceptors.…”

“…These highly functionalized compounds can be submitted to several transformations, including their use in [2+2] cycloaddition reactions, 3 Diels-Alder reactions, [4][5][6] and like Michael acceptors. 4,7 The α-phenylseleno-α,β-unsaturated esters 4 have been prepared by different routes, 2 including selenilation of ester enolates, 8 oxidative elimination of α,α-bis(phenylselanyl)esters, 8 dehydrochlorination of α-phenylseleno-β-chloro esters 8 and of α-phenylseleno-α-chloro esters, 9 and Wittig-type reactions. 6,10 On the other hand, the preparation of α-phenylselenoacrylonitriles 3 was studied in a minor extent.…”

“…6,10 On the other hand, the preparation of α-phenylselenoacrylonitriles 3 was studied in a minor extent. 2,3,4,11,12 Between the described methods for preparation of 3, those involving Wittig-type reactions are the most efficient. 4,12 Recently, Chinese authors have been described the preparation of several α-phenylseleno-α,β-unsaturated nitriles in moderate to good yields via α-phenylselenenyl cyanomethylene triphenylarsorane.…”

“…17,18 As a continuation of our studies directed toward the development of new methods for the synthesis of vinyl selenides and their great potential in organic synthesis, 2 we report herein the synthesis of α-phenylselenoacrylonitriles 3 and α-phenylseleno-α,β-unsaturated esters 4 by means of Knoevenagel reactions between phenylselenoacetonitrile 1a or ethylphenylselenoacetate 1b and aldehydes 2, using KF/Al 2 O 3 without any solvent (Scheme 1, Table 1). …”

Iron-catalyzed coupling reactions of vinylic chalcogenides with Grignard reagents

“…The multiple applications of organochalcogenium chemistry have been well described in a number of review articles 1-6 and books. 7-11 Functionalized alkynyl 12-18 and alkenyl [19][20][21][22][23] chalcogenides have a great potential in organic synthesis, since they are valuable intermediates for the selective preparation of several organic compounds.Among the many applications of vinylic selenides, divinylic selenides and vinylic sulfides, the cross-coupling reaction with Grignard reagents catalyzed by Ni 18,24-27 and Pd 28,29 to give the corresponding cross-coupled products, has been described. On the other hand, Pd 19,30 and Ni 24,[31][32][33] catalyzed cross coupling reactions and tellurium/metal exchange reactions [34][35][36][37][38][39][40][41][42] are demonstrative of the usefulness of vinylic tellurides.…”