Detail of "5659-93-8"

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Modular bis(oxazoline) ligands for palladium catalyzed allylic alkylation: unprecedented conformational behavior of a bis(oxazoline) palladium h3-1,3-diphenylallyl complex

Modular bis(oxazoline) ligands for palladium catalyzed allylic alkylation: unprecedented conformational behavior of a bis(oxazoline) palladium h3-1,3-diphenylallyl complex. Pericas, Miquel Angel; Puigjaner, Cristina; Riera, Antoni; Vidal-Ferran, Anton; Gomez, Montserrat; Jimenez, Francisco; Muller, Guillermo; Rocamora, Merce (Department de Quimica Organica Universitat de Barcelona Parc Cientific de Barcelona, Barcelona 08028, Spain). Chemistry--A European Journal, 8(18), 4164-4178 (English) 2002 Wiley-VCH Verlag GmbH & Co. KGaA. CODEN: CEUJED. ISSN: 0947-6539. DOCUMENT TYPE: Journal CA Section: 29 (Organometallic and Organometalloidal Compounds) Section cross-reference(s): 22, 23, 28 New families of enantiopure bis(oxazolines) with 4,5-trans or 4,5-cis stereochem. at the individual rings were prepd. in high yield and tested as ligands for palladium-catalyzed asym. allylic alkylation. 5659-93-8 which is the cas registry number is also used here. 2,2-Bis[4-Ar-5-CH2OR1-2-oxazolin-2-yl]propane ligands (5a-g, Ar = Ph, mesityl, 1-naphthyl; R1 = Me, CH2Ph, CHPh2, CPh3, (CH2)2OMe) were prepd. in enantiopure form starting with (R,R)-1-amino-1-aryl-3-R1O-2-propanols by reaction with dimethylmalonoyl dichloride followed by mesityl chloride induced heterocyclization, affording 4,5-trans-stereochem. of substituents of oxazoline ring. The heterocyclization induced by dibutyltin dichloride gave 4,5-cis-disubstituted 2,2-bis[4-Ph-5-CH2OCHPh2-2-oxazolin-2-yl]propane (6c). The h3-allyl palladium complexes of 5a-g, 6c and 2,2-bis[4-Ph-2-oxazolin-2-yl]propane (8a-g, 9c and 10) were used as catalysts in allylic alkylation of rac-1,3-diphenyl-2-propen-1-ol acetate by di-Me malonate exerting excellent enantioselectivities (up to 96%) for the trans oxazoline derivs., while Pd/6c system was inactive. NMR studies on palladium h3-1,3-diphenylallyl intermediates (11a, c and e) showed the presence of syn/syn- and syn/anti-allyl isomers in soln.; this resembles the first example of h3-h1-h3 isomerism in Pd allylic complexes contg. bis(oxazolines) derived from malonic acid. .