Industrielle Synthese von (+)-cis-Methyldihydrojasmonat durch enantioselektive katalytische Hydrierung; Identifizierung des Präkatalysators [Ru((−)-Me-DuPHOS)(H)(η6-1,3,5-cyclooctatrien)](BF4)

Abstract

Die Jasmonoide, ()-cis-Jasmonsäure und ihre Derivate, haben zahlreiche phytobiologische Aktivitäten, [1] und der Methylester ()-cis-Methyljasmonat [2] ()-1 weist unter anderem auch einen Geruch auf, [3] der in der Parfümerie hoch geschätzt wird. [4] Das Studium der Jasmonoide begann 1962, als eine weitgehend äquilibrierte Mischung von (À)-trans-Methyljasmonat (À)-2 (Hauptkomponente, siehe unten) und CO 2 Me O CO 2 Me O CO 2 Me O CO 2 Me O CO 2 Me O (+)-1 (-)-2 (+)-3 (-)-4 5 [*] Dr.

Synthesis of Chiral Heterocyclic Phosphines for Application in Asymmetric Catalysis

“…BPE and DuPHOS ligands were also employed in the asymmetric hydrogenation of prochiral Nacyl enamides to give acetylated amines in 92-99 %ee [98]. Good results were likewise achieved with a [RuH(COT)(MeDuPHOS)]BF 4 complex [99] (COT=cycloocta-1,3,5-triene) in the diastereo-and enantioselective hydrogenation of a 2,3-disubstituted cyclopent-2-enone derivative to give the flavouring compound methyl dihydrojasmonate [100]. A cationic [Rh(Me-DuPHOS)(acetone) 2 ] + -complex has been successfully employed for the asymmetric intramolecular hydroacylation of 4-substituted pent-4-enals to form -substituted cyclopentanones [101].…”

A Versatile and High‐Yield Route to Active and Well‐Defined Catalysts [Ru(bisphosphane)(H)(solvent) 3 ](BF 4 )

“…In the mid 1980s, the focus changed from Rh to lower costing Ru, and it is now evident that the most versatile and often the most active chiral catalysts for hydrogenation of functionalized alkenes and ketones are [Ru II ($_{\rm PP}^{\frown }$ )] complexes 2. Despite this, only two of the Ru systems known prior to the present work3 possess features that parallel those of [Rh($_{\rm PP}^{\frown }$ )(sol) 2 ] + , and the importance of these two may have been overlooked. Both are hydrido, monocationic complexes of the type [Ru($_{\rm PP}^{\frown }$ )(H)(sol) n ] + ( n =2, 3).…”

“…(3)]. Small amounts (∼3 %) of [Ru((−)‐Me‐DuPHOS)(H)( η 4 ‐cod′)](BF 4 ) ( 8 ) also form,3 which we identify and discuss below. Addition of more than one equivalent of (−)‐ 2 leads to the known15 [Ru((−)‐Me‐DuPHOS) 2 (H)] + by displacement of the cot ligand.…”

“…Our previous paper3 describes the first synthesis of a new prototypal catalyst precursor, [Ru((−)‐Me‐DuPHOS)(H)( η 6 ‐cot)](BF 4 ) ( 1 ; cot=1,3,5‐cyclooctatriene), made in one step from [Ru(1,2:5,6 ‐η‐ cod)( η 3 ‐methallyl) 2 ], (−)‐Me‐DuPHOS5c ((−)‐ 2 ), and HBF 4 ⋅Et 2 O. The catalyst precursor 1 was identified during the development of an industrial process for making the fragrance chemical (+)‐ cis ‐methyl dihydrojasmonate (+)‐ 3 by an enantioselective hydrogenation of the doubly functionalized, tetrasubstituted alkene 4 , a vinylogous β ‐oxoester [Eq.…”

“…Our first route3 to [Ru($_{\rm PP}^{\frown }$ )(H)( η 6 ‐cot)](BF 4 ) is difficult to adapt to $_{\rm PP}^{\frown }$ other than Me‐DuPHOS ( 2 ). We thus sought a more general, simple, and high‐yielding synthesis.…”