Ordering information is given on any current masthead page.(11) The CD curve of (-)-14 contains two Cotton effects, one is due to the enone-enone interaction and the other is due to the helicity of the twisted enone in the C ring, therefore the difference between curve b and curve a shows the real exciton-split CD curve of the enone-enone interaction.

The established standard ketone hydrogenation (abbreviated HY herein) precatalyst [Ru(Cl)(2)((S)-tolbinap)[(S,S)-dpen]] ((S),(S,S)-1) has turned out also to be a precatalyst for ketone transfer hydrogenation (abbreviated TRHY herein) as tested on the substrate acetophenone (3) in iPrOH under standard conditions (45 degrees C, 45 bar H(2) or Ar at atmospheric pressure). HY works at a substrate catalyst ratio (s:c) of up to 10(6) and TRHY at s:c<10(4). Both produce (R)-1-phenylethan-1-ol ((R)-4), but the ee in HY are much higher (78-83 %) than in TRHY (4-62 %). In both modes, iPrOK is needed to generate the active catalysts, and the more there is (1-4500 equiv), the faster the catalytic reactions. The ee is about constant in HY and diminishes in TRHY as more iPrOK is added. The ketone TRHY precatalyst [Ru(Cl)(2)((S,S)-cyP(2)(NH)(2))] ((S,S)-2), established at s:c=200, has also turned out to be a ketone HY precatalyst at up to s:c=10(6), again as tested on 3 in iPrOH under standard conditions. The enantioselectivity is opposite in the two modes and only high in TRHY: with (S,S)-2, one obtains (R)-4 in up to 98 % ee in TRHY as reported and (S)-4 in 20-25 % ee in HY. iPrOK is again required to generate the active catalysts in both modes, and again, the more there is, the faster the catalytic reactions. The ee in TRHY are only high when 0.5-1 equivalents iPrOK are used and diminish when more is added, while the (low) ee is again about constant in HY as more iPrOK is added (0-4500 equiv). The new [Ru(H)(Cl)((S,S)-cyP(2)(NH)(2))] isomers (S,S)-9 A and (S,S)-9 B (mixture, exact structures unknown) are also precatalysts for the TRHY and HY of 3 under the same conditions, and (R)-4 is again produced in TRHY and (S)-4 in HY, but the lower ee shows that in TRHY (S,S)-9 A/(S,S)-9 B do not lead to the same catalysts as (S,S)-2. In contrast, the ee are in accord with (S,S)-9 A/(S,S)-9 B leading to the same catalysts as (S,S)-2 in HY. The kinetic rate law for the HY of 3 in iPrOH and in benzene using (S,S)-9 A/(S,S)-9 B/iPrOK or (S,S)-9 A/(S,S)-9 B/tBuOK is consistent with a fast, reversible addition of 3 to a five-coordinate amidohydride (S,S)-11 to give an (S,S)-11-substrate complex, in competition with the rate-determining addition of H(2) to (S,S)-11 to give a dihydride [Ru(H)(2)((S,S)-cyP(2)(NH)(2))] (S,S)-10, which in turn reacts rapidly with 3 to generate (S)-4 and (S,S)-11. The established achiral ketone TRHY precatalyst [Ru(Cl)(2)(ethP(2)(NH)(2))] (12) has turned out to be also a powerful precatalyst for the HY of 3 in iPrOH at s:c=10(6) and of some other substrates. Response to the presence of iPrOK is as before, except that 12 already functions well without it at up to s:c=10(6).

Scheme 1. Reaction paths with alternative a-agostic transition states leading to threo-2 (left) and erylhro-2 (right) via two consecutive olefin insertions with opposite and identical olefin orientations, respectively. of the migrating alkyl unit, has been proposed by Brookhart and Green." 21 The observations reported here constitute the first experimental evidence for such an a-agostic transition state in zirconocene-catalyzed olefin polymerizations.['31 Experimental (E-I-deuterio-1-hexene: Reaction of 1-hexyne with 1 equiv. diisobutylaluminum hydride in toluene at 0 "C; cleavage with D,O and fractional distillation [G. Wjlke, H. Miiller, Justus Liehigs Ann. Chem. 629 (1960) 222, G . Zweifel, R L. Miller, J. Am. Chem. Sac. 92 (1970) 66781; the 'H-NMR spectrum (doublet of triplets, b = 4.98, ' J = 17.1, "J = 1.5 Hz, 1 H; symmetric multiplet, b = 5.82, 1 H [14]) indicates that (Q-1-deuterio-1-hexene is the only olefin present. (Z)-1 -deuterio-1-hexene-Cleavage with H,O of the hydroalumination product of I-deuterio-1-hexyne [G. W. Kabalka, R. J. Newton, J. Jacobus, J. Org. Chem. 43 (1978) 15671. 'H NMR: 6 = 4.91 (d, ' J = 10.4 Hz), 5 80(m). The presence of ca. 15% [D,]hexane, 10% toluene and 5 % [D,lbutane, indicated by gas chromatography does not interfere with the catalysis or with the isolation of the hydrodimer 2; traces of I-hexyne have to be removed by prolonged stirring with and distilling from solvent-free n-butyllithium.Hydrodimerizations: 3.5 mL (33 mmo!) of (Q-or (a-1-deuterio-1-hexene, 430 mg MA0 (6.6 mmol CH'AIO, Schering AG, M , =z 1300, in 4.5 mL toluene) and 33 pmol of either rac-1 or (C,H,),ZrCI, in 0.5 mL toluene (all under N,)were exposed in a 50 mL autoclave at -5°C to initial H, pressures of 20 and 15 atm. respectively. for 16-20 h; during this time H, pressures fell by ca. 5 atm After quenching with 10 mL 1.5 M aq. HCI and separation ofthe organic layer, 2 was isolated by fractional distillation. Admixtures of ca. 5 % 6,7-[D,]n-dodecane (the tail-to-tail rnis-insertion product) gave weak D-NMR signals just separable from the adjacent signal of eryrhro-2.

Prototypes of new families of precatalysts and catalysts, [Ru((−)‐Me‐DuPHOS)(H)(η6‐1,3,5‐cyclooctatriene)](BF4) and the derived “[Ru((−)‐Me‐DuPHOS)(H)(sol)](BF4)”, are presented. They are used in an industrial, catalytic, enantioselective hydrogenation that leads to (+)‐cis‐methyl dihydrojasmonate [Eq. (1)]. This stereoisomer is the odorant component of an important, large volume perfumery chemical. P−P=Diphosphane ligand (for example, Me‐DuPHOS=1,2‐bis((2R,5R)‐2,5‐dimethylphospholanyl)benzene); sol=solvent.

Under the conditions of the Wharton reaction, the (±)‐epoxy‐γ‐dihydroionones 2 and 3 are transformed into the allylic alcohols 4–10. γ‐Damascols 4, 5 and 8 were oxidised to cis‐ and trans‐γ‐damascone 12 and 13. Alternatively, dehydro‐γ‐damascol 18 was obtained by Wittig rearrangement of butinyl ether 17, and converted into damascones 12 and 13.

Herrn Dr. Roger Firmenich zum 65. Geburtstag gewidmet (29. VI. 71) Summary. The 6 R configuration of (+)-cis-y-irone [( +)-4] was established by chemical correlation with (-)-camphor. (+)-cis-y-irone [( +)-41 was converted into (+)-cis-a-irone [( +)-11, (-)-trans-a-irone [( -)-21, and (+)-p-irone [(+)-31, which thereforc also have the 6 R configuration. The 2 S configurations of (+)-cis-a-irone [(+)-I] and (+)-trans-cc-irone [(+)-2] were determined by comparison of their circular dichroism with that of R-a-ionone [( +)-51. The 2s configuration of (+)-cis-y-irone [ ( +)-41 was established by chemical correlation with (+ )-cis-cc-irone [(+ i-11.Der Strukturbeweis fur tc-und @-Iron durch Synthese [l] [Z] gelang erst mehr als 75 Jahre nach ihrer Entdeckung [3] im atherischen 01 einer Schwertlilienart [4j. Bis heute ist die Aufklarung der Stereochemie dieser Serie von Veilchenriechstoffen uber Ansatze nicht hinausgegangen. So versuchte man z. €3. die relativen Konfigurationen uber die Auwers-Skita'sche Regel zuzuordnen [S]. Ob diese Regel hier in ihrer urspriinglichen oder revidierten [6] Form angewendet werden kann, ist allerdings fraglichl). Ebenso reichen die bisher vorliegenden Fakten fur die Festlegung der Chiralitatszentren nicht aus [7].In der vorliegendeii Arbeit werden nun Versuclie beschrieben, die zur Aufklarung der absoluten Konfiguration der Irone 1-4 fuhrten.(+)-1

SummaryIn view of the demonstration by Jaenicke et a/. that different Iris varieties produce enantiomeric irones [6], we complement our 1971 paper on the stereochemistry of the irones [3]. 1) We give what information we have on the origin of the Iris oil used in [3]; 2) we show that we and Ruzicka et a/. on whose degradation work our determination of the C(2)-configurations was based had the same irones in hand; 3) we summarize independent assignments of the C(2)-configurations and the relative configurations of the a-irones. 4) We also describe the identification of a trace of the 'missing' trans-yirone in our oil, and 5 ) revise the preferred conformation of the cis-a-irones in solution.

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.