Highly Efficient, Recyclable Pd(II) Catalysts with Bisimidazole Ligands for the Heck Reaction in Ionic Liquids.

Abstract

AlkenesAlkenes Q 0083 Highly Efficient, Recyclable Pd(II) Catalysts with Bisimidazole Ligands for the Heck Reaction in Ionic Liquids. -The phosphine-free catalyst system presented can be recycled up to five times without loss of catalytic activity. -(PARK, S. B.; ALPER*, H.; Org. Lett. 5 (2003) 18, 3209-3212; Dep. Chem., Univ. Ottawa, Ottawa, Ont. K1N 6N5, Can.; Eng.) -Nuesgen 52-074

Ionic Liquids Recycling for Reuse

“…It was found that no decrease in yield or purity of the products when the ionic liquids were both reused. The results are listed in [Park & Alper, 2003], Bischler-Napierlaski cyclisation [Judeh et al, 2002], Beckmann rearrangement [Ren et al, 2001] addition of thiols to unsaturated ketones [Yadav et al, 2003] and l-proline catalysed aldol reaction [Loh et al, 2002]. et al 2009].…”

“…These ILs have been employed as excellent and recyclable medium for a wide array of reactions; e.g., Heck reaction [Park & Alper, 2003], Bischler-Napierlaski cyclisation [Judeh et al, 2002], Beckmann rearrangement [Ren et al, 2001], addition of thiols to unsaturated ketones [Yadav et al, 2003], l-proline catalysed aldol reaction [Loh et al, 2002] . Other examples where ILs have been used as a reaction media include, but not limited to, Diels-Alder reactions [Reinhardt, 2009;Doherty, 2004;Song, 2001], Friedel-Crafts alkylation and acylation reactions [Xiao, 2006;Xiao & Malhotra, 2005;Ross & Xiao, 2002;Itoh, 2001;Stark et al, 1999], hydroformylation reactions [Magna et al, 2007;Sharma, 2009], Pd-mediated C-C bond formation [Park & Alper, 2003], alkene polymerisation [Hardacre et al, 2002], and biotransformations [Bornscheuer & Kazlauskas, 2006]. Bortolini et al (2002) accomplished the recycling of [bmim] [PF 6 ] by washing with an aqueous solution of NaHSO 3 and then with water.…”

Jaunas metodes hirālu 4-aril-3,4-dihidrokumarīnu sintēzē

“…Vēl viena vienkārša metode ,-nepiesātinātu karbonilsavienojumu iegūšanai ir palādija katalizēta akrilskābes atvasinājumu un arilhalogenīdu sametināšanas reakcija (Heka reakcija). [51][52][53][54][55] Pārbaudot šo iespēju, vispirms mēģinājām iegūt kanēļskābi 53a 1-benziloksi-2-brom- Analizējot literatūru, redzams, ka atbilstošo kanēļskābes esteru iznākums Heka sametināšanā izmantojot arilbromīdus, ir zems (7-24%), 53 savukārt jodīdi parasti dod augstus iznākumus (83-95%). 51,52,54,55 Diemžēl atbilstošā jodīda mūsu rīcībā nebija.…”

“…[51][52][53][54][55] Pārbaudot šo iespēju, vispirms mēģinājām iegūt kanēļskābi 53a 1-benziloksi-2-brom- Analizējot literatūru, redzams, ka atbilstošo kanēļskābes esteru iznākums Heka sametināšanā izmantojot arilbromīdus, ir zems (7-24%), 53 savukārt jodīdi parasti dod augstus iznākumus (83-95%). 51,52,54,55 Diemžēl atbilstošā jodīda mūsu rīcībā nebija.…”