Construction of Novel Polycyclic Ring Systems by Transition-Metal-Catalyzed Cycloisomerization of Ene−Ene−Ynes. Interception of a Carbenoid Intermediate in Skeletal Reorganization of Enynes

Chatani, Naoto; Kataoka, and Ken; Murai, Shinji; and, Naoyuki Furukawa; Seki, Yasutaka

doi:10.1021/ja981877p

Cited by 203 publications

(138 citation statements)

References 21 publications

Supporting

Mentioning

118

Contrasting

Unclassified

Order By: Relevance

“…Modifying the steric or electronic properties of these acyclic enol acetates had only small effects on the enantioselectivities (observed ranging from 80 to 85 % ee). For the enol acetate derived from acetophenone, the enantioselectivity obtained with Rh ± (R,S,R,S)-Me-PennPhos (entries 7 and 8) was comparable to those obtained with Rh ± DuPhos compounds (77 % ee in THF catalyzed by [Rh(MeDuPhos)(cod)]BF 4 , 89 % ee in MeOH with [Rh(Me-DuPhos)-(cod)]OTf, [3f] OTf trifluormethanesulfonate). Further modification of the Rh ± PennPhos structure may lead to practical catalysts for the hydrogenation of electron-rich acyclic enol acetates.…”

Section: Dedicated To Professor Helmut Werner On the Occasion Of His mentioning

confidence: 59%

“…Our previous work has shown that this novel motif imparts valuable properties to this catalytic system. [4] Since enol acetates are likely to be chelating substrates, the constrained geometry of the cyclic enol acetates may enhance recognition toward chiral transition metal complexes compared with acyclic enol acetates.…”

Section: Dedicated To Professor Helmut Werner On the Occasion Of His mentioning

confidence: 99%

“…Given the propensity of chloro-ruthenium complexes to adopt face-sharing bioctahedral structures, [12,15] we were intrigued by the fact that the hypothetical binary carbonylchloro anion [Ru 2 (m-Cl) 3 (CO) 4 Cl 2 ] À (7) has not been reported, whereas the dianionic complex [Ru 2 (m-Cl) 2 (CO) 4 Cl 4 ] 2À (8) is readily available by thermal decarbonylation of 1 or 2 in the presence of one equivalent of halide ion per ruthenium unit. [16] We have now discovered a route to 7: it is readily prepared by thermal decarbonylation of 2 in dimethylacetamide (dma) in the presence of [PPN]Cl (Scheme 5).…”

mentioning

confidence: 99%

“…The solid residue was washed with hexane. Recrystallization from dichloromethane/hexane gave [PPN]-7 (1390 mg, 90 % yield In the past few years Power et al, [1] Schnick et al, [2] and others [3,4] have shown that amino and imino derivatives containing silicon can undergo interesting reactions. In this respect they resemble the oxygen derivatives to some extent, but they can also differ from them quite considerably.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Reactions of a Transient Carbonyl(chloro)(hydrido)ruthenium(II) Complex with Ethylene, Alkynes, and CO; Chemistry of the New Anion [Ru2(CO)4Cl5]−

Fauré

Maurette

Donnadieu

et al. 1999

Angew. Chem. Int. Ed.

View full text Add to dashboard Cite

A 97% yield of [Ru (CO) ] (2) in 20 minutes is obtained simply by treating [Ru(CO) Cl (thf)] with KOH under CO (1 atm). The reduction to Ru can be explained in terms of the facile reductive elimination of HCl from the transient hydrido complex 1. Though elusive, the latter can be intercepted by olefins or alkynes to produce trappable alkyl or alkenyl complexes such as 3 and 4.█ denotes a vacant coordination site.

show abstract

Section: Dedicated To Professor Helmut Werner On the Occasion Of His mentioning

confidence: 59%

Section: Dedicated To Professor Helmut Werner On the Occasion Of His mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Reactions of a Transient Carbonyl(chloro)(hydrido)ruthenium(II) Complex with Ethylene, Alkynes, and CO; Chemistry of the New Anion [Ru2(CO)4Cl5]−

Fauré

Maurette

Donnadieu

et al. 1999

Angew. Chem. Int. Ed.

View full text Add to dashboard Cite

show abstract

“…T ransition metal-catalyzed carbocyclizations of 1,6-enynes A (1-4), such as cycloisomerization (5)(6)(7)(8)(9)(10)(11), metathesis (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), skeletal reorganization (23)(24)(25)(26), and ene reactions (27)(28)(29), are useful synthetic methods leading to five-membered rings (Scheme 1). By contrast, we challenged six-membered cyclization of 1,6-enynes of type B by alkyne-metal-or carbonyl (Y ϭ CAO)-Lewis acid complexation by 6-(2, 4) ene-type cyclization (30) (after [1,5]-hydrogen shift numbering) (Oppolzer's type II) (31) (Scheme 2).…”

mentioning

confidence: 99%

Palladium-catalyzed carbocyclization of 1,6-enynes leading to six-membered rings or oxidized five-membered trifluoroacetates

Mikami

Hatano

2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We describe palladium-catalyzed carbocyclization of 1,6-enynes leading to six-membered rings by water-originated hydride addition. Mechanistic features of this anomalous carbocyclization and isolation of a chiral five-membered C-Pd intermediate as an oxidized form of trifluoroacetate are also reported.T ransition metal-catalyzed carbocyclizations of 1,6-enynes A (1-4), such as cycloisomerization (5-11), metathesis (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), skeletal reorganization (23-26), and ene reactions (27)(28)(29), are useful synthetic methods leading to five-membered rings (Scheme 1). By contrast, we challenged six-membered cyclization of 1,6-enynes of type B by alkyne-metal-or carbonyl (Y ϭ CAO)-Lewis acid complexation by 6-(2, 4) ene-type cyclization (30) (after [1,5]-hydrogen shift numbering) (Oppolzer's type II) (31) (Scheme 2). A six-membered ring was obtained, however, not as the expected (Z)-olefin C. Herein, we report that dicationic palladium-catalyzed carbocyclization of 1,6-enynes (32, 33), unlike ruthenium-, rhodium-, and platinum-catalyzed metathesis, leads to the (E)-six-membered rings (D), wherein water-derived hydride is involved to fix the (E)-olefin geometry. We also present the mechanistic features of this anomalous carbocyclization and isolation of a chiral five-membered C-Pd intermediate (E) as an oxidized trif luoroacetate. MethodsGeneral. 1 H, 13 C, and 31 P NMR spectra were measured on Varian Gemini 300 (300 MHz) and Varian Gemini 400 (400 MHz) spectrometers. IR spectra were measured on a FT͞IR-5000 spectrometer (Jasco, Tokyo). Optical rotations were measured on a Jasco DIP-370. Liquid chromatographic analyses (HPLC) were conducted on a Jasco PU-980, LG-980 -02, DG-980 -50, AS-950, and CO-966 instrument equipped with model UV-975 spectrometers as an ultraviolet light. Peak areas were calculated by JASCO-BORWIN (WINDOWS NT) as an automatic integrator. Capillary GC analyses were conducted on a Shimadzu GC-14B instrument by using N 2 (75 kPa) as a carrier gas. Peak areas were calculated by a Shimadzu C-R6A as an automatic integrator; chiral columns were CPCyclodextrin-␤-2,3,6-M-19 (i.d. 0.25 mm ϫ 25 m; Chrompack, GL Sciences, Tokyo) and CP-Chirasil-Dex CB (i.d. 0.32 mm ϫ 25 m; Chrompack, GL Sciences). The split ratio was 100:1. Analytical TLC was performed on glass plates (Merck Kieselgal 60 F 254 ; layer thickness, 0.25 and 0.2 mm). Visualization was accomplished by UV light (254 nm), anisaldehyde, KMnO 4 , and phosphomolybdic acid. Column chromatography was performed on Kanto Silica Gel 60N (spherical, neutral; Kanto Kagaku, Tokyo). All experiments were carried out under an argon atmosphere unless otherwise noted. 5,5Ј-diylbis(diphenylphosphine) [(S)-SEGPHOS] were provided by Takasago International (Tokyo).Typical Procedure for Pd-Catalyzed Ene-Type Cyclization. To a Pyrex test tube well degassed DMSO (2.0 ml) was injected, and argon was charged. [(MeCN) 4 Pd](BF 4 ) 2 (11.1 mg, 0.025 mmol) and (R)-BINAP (17.1 mg, 0.050 mmol) were added under an argon atmosphere, and the suspensi...

show abstract

Optimization in organic synthesis

Snieckus

1999

Med. Res. Rev.

View full text Add to dashboard Cite

Art is always a bonus to synthesis . . . . the artistic aspect of synthesis, beautiful and marvelous as it is, should not be a justification for carrying out a total synthesis. If your problem is truly essential then you don't care about the elegance. The more essential your first E is, the less important your last E becomes." 1 "Will we be able to recapture the many millions of presumed 'transient'natural products that were evolutionarily de-selected along the paths that eventually led to the natural products synthesized on Earth today? . . . I cannot imagine that in a young synthetic chemist's lifetime, it will not be accomplished." 2 Organic Synthesis, quo vadis? 3 has been a phrase, perhaps in a more modern language, on the lips of the practitioners of this demanding science-art, undoubtedly from the earliest times 4 but more vigorously in the last two decades. 5 Comparison of achievements of yesterday 6 and today 7 suggests progress in our abilities to construct molecules of complexity, with higher stereocontrol, faster analysis, and greater prediction of eventual success. However, the practical aspects, on any scale, of brevity, efficiency, safety, eco-consciousness, and energy-and resource-frugality remain, as noted by a major synthetic craftsman, 8 crudely addressed. The Y2K symbolism is perhaps also appropriate for urgently dedicating our efforts to making headway in the solution of these interrelated goals.Our central science 5a progresses on fronts of method development and total synthesis with a great deal of cross-talk and interdependency (see Fig. 1). The burgeoning literature of new methods suggests that 70% are not repeated, perhaps even in the original laboratories, a situation with dire consequences for ascertaining true yield ranges and reproducibility a la the Org. Syn. religion. Furthermore, as judged from a cursory glance of tables in recent journals, much is left to be desired in giving confidence to the user that a method has generality (substrate diversity, FG and steric tolerance, catalyst or reagent minimization, and temperature and solvent optimization). Although the beauty of judiciously modeled use of PGs is to be applauded, 9 FG protection is a continuing embarrassment and annoyance. Synthetic chemists are challenging the dogma by daring the multi-FG molecules to behave in the manner desired. Ugi multicomponent reactions 10 and combinatorial synthesis 11 will undoubtedly soon influence the PG-expediency problem. In industry, statistical programs 12 at times drive optimization of reactions thus meeting the normal intense time constraints to produce mulit-kg of commercial substances.Atom-economy, a term coined by another influential synthetic chemist, 13 has brought awareness of an issue to academic scientists which their industrial process and development colleagues un-

show abstract

Construction of Novel Polycyclic Ring Systems by Transition-Metal-Catalyzed Cycloisomerization of Ene−Ene−Ynes. Interception of a Carbenoid Intermediate in Skeletal Reorganization of Enynes

Cited by 203 publications

References 21 publications

Reactions of a Transient Carbonyl(chloro)(hydrido)ruthenium(II) Complex with Ethylene, Alkynes, and CO; Chemistry of the New Anion [Ru2(CO)4Cl5]−

Reactions of a Transient Carbonyl(chloro)(hydrido)ruthenium(II) Complex with Ethylene, Alkynes, and CO; Chemistry of the New Anion [Ru2(CO)4Cl5]−

Palladium-catalyzed carbocyclization of 1,6-enynes leading to six-membered rings or oxidized five-membered trifluoroacetates

Optimization in organic synthesis

Contact Info

Product

Resources

About