60416-25-3Relevant academic research and scientific papers
Regioselective rhodium-catalyzed hydroformylation of 1,3-dienes to highly enantioenriched β,γ-unsaturated aldehyes with diazaphospholane ligands
Watkins, Avery L.,Landis, Clark R.
, p. 164 - 167 (2011/04/12)
Regioselective and enantioselective rhodium-catalyzed hydroformylation of 1,3-dienes with chiral bisdiazaphospholane ligands yields β,γ- unsaturated aldehydes that retain a C=C functionality for further conversion. The reaction conditions are mild, featuring low catalyst loadings (0.5 mol %), pressures readily obtained in glass bottles, and convenient reaction times (1.5-12 h). Optimized reaction conditions produce high enantioselectivity (>90% ee), regioselectivity (88-99%), and conversion to β,γ- unsaturated aldehydes (99%) for ten 1,3-dienes encompassing a variety of substitution patterns.
A novel synthesis of γ,δ-unsaturated aldehydes from α-formyl-γ-lactones
Snowden, Roger L.,Brauchli, Robert,Linder, Simon
, p. 1216 - 1225 (2011/09/16)
A preparatively useful one-step transformation of γ,γ- disubstituted α-formyl-γ-lactones into trisubstituted γ,δ-unsaturated aldehydes is described, by means of catalytic amounts of either AcOH or AcOEt in the vapor phase over a glass support. A mechanistic rationale is proposed. Copyright
Studies concerning the electrophilic amino-alkene cyclisation for the synthesis of bicyclic amines
Klein, Johannes E. M. N.,Mueller-Bunz, Helge,Evans, Paul
supporting information; experimental part, p. 986 - 995 (2009/05/30)
The bromination of a series of cyclohexenyl substituted secondary amines 1a-i has been investigated using Br2, PHT and NBS. In the case of Br2 and NBS the secondary amines preferentially undergo N-bromination. In contrast, PHT cleanly affords the products of alkene dibromination. In the case of Br2 the N-bromo species then give the products of alkene dibromination, albeit less efficiently. On subsequent treatment with K2CO3 these dibromides form the corresponding hexahydroindoles 2a-h and octahydroquinoline 2i. The presence of an N-substituent bearing a stereogenic centre (1h and 1i) was studied and the products 2h and 2i were isolated with no diastereoselectivity. When NBS was used a novel cyclisation, forming bromo-substituted octahydroindoles 9a,b and d, was observed. In relation to this sequence it was shown that these products were not intermediates in the former Br2/PHT processes and that the reaction only proceeded in the presence of the succinimide by-product of N-bromination.
γ,δ- and δ,ε-unsaturated aldehydes from γ- and δ-lactones in one step: Preliminary communication
Giersch, Wolfgang,Naef, Ferdinand
, p. 1697 - 1703 (2007/10/03)
A one-step transformation of δ- and δ-(spiro)lactones into δ,δ- and δ,ε-unsaturated aldehydes with an excess of formic acid in the vapor phase over a supported manganese catalyst is described for the first time. The scope and limitations of this new reaction are shown with different lactones as substrate, and a mechanistic rationale is proposed.
PROCESS FOR THE DIRECT CONVERSION OF LACTONES INTO UNSATURATED KETONES OR ALDEHYDES
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Page 9, (2008/06/13)
The present invention refers to a process for the preparation of unsaturated ketones or aldehydes by pyrolysis of a lactone, in the presence of a reducing agent such as molecular hydrogen or a carboxylic acid, and in the presence of a catalyst, optionally
An advanced intermediate for the synthesis of (±)-pumiliotoxin C and its analogues
Shao, Zhi-Hui,Peng, Fang-Zhi,Chen, Jing-Bo,Wang, Chen-Ying,Huang, Rong,Tu, Yong-Qiang,Li, Liang,Zhang, Hong-Bin
, p. 2031 - 2038 (2007/10/03)
Compound 1 as a versatile intermediate for the synthesis of (±)-pumiliotoxin C and its analogues was prepared from commercially available cyclohexanone. The key step in the synthesis was the construction of octahydroquinoline ring by a stereoselective ami
Intramolecular [2+2] photocycloaddition-fragmentation: Facile entry to a novel tricyclic 5-6-7 ring system
Hong, Bor-Cherng,Chen, Shang-Hung,Kumar, Ellappan Sampath,Lee, Gene-Hsiang,Lin, Kuan-Jiuh
, p. 917 - 926 (2007/10/03)
An expeditious route to a novel 5-6-7 tricyclic ring system is described. The chemistry capitalizes on an enantioselective glyoxylate-ene reaction, enzymatic resolution as well as a [2+2] photocycloaddition-fragmentation.
Complementary regioselective cyclopropyl ring openings of 6- formyl-spirobicyclo[5.2]octane mediated by TMSC1 and TBAI
Huang, He,Forsyth, Craig J.
, p. 16341 - 16348 (2007/10/03)
Absolute control over the regioselectivity of trimethylsilyl halide-induced cyclopropane fragmentation of a spirofused cyclopropyl carboxaldehyde has been achieved by simply varying the reaction stoichiometry and the nature of the halide. Treatment of 6-formyl- spirobicyclo[5.2]octane with a large excess of TMSC1 gave 3-(1- chlorocyclohexyl)propanal (84% yield), whereas 2-(1- iodomethylcyclohexyl)ethanal (86% yield) was obtained using 10 equivalents each TMSC1 and n-Bu4NI (TBAI). Use of only a moderate excess of TMSC1 or TMSC1 and TBAI gave the rearranged product 3-(1- cyclohexenyl)-propanal.
Asymmetric hydroformylation of conjugated dienes catalyzed by chiral phosphine-phosphite-Rh(I) complex
Horiuchi, Toshihide,Ohta, Tetsuo,Shirakawa, Eiji,Nozaki, Kyoko,Takaya, Hidemasa
, p. 7795 - 7804 (2007/10/03)
Asymmetric hydroformylation of conjugated dienes has been investigated using (R,S)-BINAPHOS-Rh(I) complex as a catalyst [(R,S)-BINAPHOS = (R)-2-(diphenylphosphino)-1,1'-binaphthalen-2'-yl (S)-1,1'-binaphthalene-2,2'-diyl phosphite]. Optically active β,γ-unsaturated aldehydes were obtained in high regio- (78-94%) and enantioselectivities (80-97% ee) from 1-vinylcyclohexene, 4-methyl-1,3-pentadiene, and (E)-1-phenyl-1,3-butadiene. On the other hand, hydroformylation of 1,3-butadiene gave achiral product, (E)- and (Z)-3-pentenal, in up to 95% selectivity. (R)-(E)-2-Methyl-3-pentenal was formed as the major product from both (E)- and (Z)-1,3-pentadiene, but enantioselectivity of the reaction was low. Mechanistic aspects are also discussed.
Highly enantioselective hydroformylation of olefins catalyzed by rhodium(I) complexes of new chiral phosphine-phosphite ligands
Nozaki, Kyoko,Sakai, Nozomu,Nanno, Tetsuo,Higashijima, Takanori,Mano, Satoshi,Horiuchi, Toshihide,Takaya, Hidemasa
, p. 4413 - 4423 (2007/10/03)
A new chiral phosphine-phosphite ligand, (R)-2-(diphenylphosphino)- 1,1'-binaphthalen-2'-yl (S)-1,1'-binaphthalene-2,2'-diyl phosphite [(R,S)- BINAPHOS, (R,S)-2a], was synthesized. Its Rh(I) complex was prepared, and its structure has been characterized by 1H and 31P NMR spectroscopy. Using Rh(I) complexes of (R,S)-2a and its enantiomer, highly enantioselective hydroformylation of styrene has been performed (94% ee, iso/normal = 88/12). The catalyst system was also effective for a variety of other olefins. Some other phosphine-phosphite ligands bearing 1,1'-binaphthyl and biphenyl backbones, such as (S)-3,3'-dichloro-6-(diphenylphosphino)-2,2',4,4'- tetramethylbiphenyl-6'-yl (R)-1,1'-binaphthalene-2,2'-diyl phosphite [(S,R)- BIPHEMPHOS. (S,R)-5a], (R,R)-2a, (R,S)-2b, (R)-2c, and (R)-5b, were tested for asymmetric hydroformylation. The results indicate that the sense of enantioface selection for the prochiral olefins is mainly determined by the absolute configuration of the phosphine site, for example, the (R)-2- (diphenylphosphino)-1,1'-binaphthalen-2'-yl group in (R,S)-2a. The relative configurations of the two biaryl groups in the phosphine-phosphites play crucial roles in the degree of the enantioselectivities, that is, the (R,S)- isomer generally gives products in high ee's and the (R*,R*)-isomer does in low ee's. Treatment of Rh(acac)[(R,S)-2a] with a 1:1 mixture of carbon monoxide and hydrogen gave a hydridorhodium complex. RhH-(CO)2[(R,S)-2a], as a single species. Trigonal bipyramidal structure is suggested for this complex, in which the hydride and the phosphite moiety are located at the apical positions and the phosphine and the two carbonyls occupy the equatorial positions. The interchange of the phosphine and the phosphite sites with each other through rapid pseudorotations has not been observed in RhH(CO)2[(R,S)-2a]. The structural deviations of the monohydride complexes from an ideal trigonal bipyramid seem to be larger in (R*,R*)-isomers than in the corresponding (R*,S*)-isomers. The existence of only one active species involved in the Rh(1)-(R,S)-2a-catalyzed hydroformylation has been manifested by the plot of ln([R]/[S]) of the hydroformylation product vs the reciprocals of the reaction temperatures. The higher thermodynamic stability of Rh(acac)[(R,S)-2a] than its diastereomer Rh(acac)[(R,R)-2a] is demonstrated in relation to the restricted configuration of (R)-2c to (R,S)- 2c in its complex formation with Rh(1).
