56539-60-7Relevant academic research and scientific papers
Ru-Catalyzed Migratory Geminal Semihydrogenation of Internal Alkynes to Terminal Olefins
Song, Lijuan,Feng, Qiang,Wang, Yong,Ding, Shengtao,Wu, Yun-Dong,Zhang, Xinhao,Chung, Lung Wa,Sun, Jianwei
, p. 17441 - 17451 (2019/11/03)
Semihydrogenation of alkynes to alkenes represents a fundamentally useful transformation. In addition to the well-known cis- and trans-semihydrogenation, herein a geminal semihydrogenation of internal alkynes featuring 1,2-migration is described, which pr
Enantioselective NiH/Pmrox-Catalyzed 1,2-Reduction of α,β-Unsaturated Ketones
Chen, Fenglin,Zhang, Yao,Yu, Lei,Zhu, Shaolin
, p. 2022 - 2025 (2017/02/15)
The enantioselective 1,2-reduction of α,β-unsaturated ketones was achieved using a NiH catalyst in the presence of pinacolborane. This mild process represents a general method to access a wide variety of structurally diverse α-chiral allylic alcohols in excellent yields and enantioselectivity, as well as very high levels of ambidoselectivity for 1,2- over 1,4-reduction. Furthermore, for reactions on a 10 mmol scale, catalyst loadings as low as 0.5 mol % could be employed to deliver product without any detrimental effect on the yield, enantio-, or ambidoselectivity.
New catalytic route to (E)-β-silyl-α,β-unsaturated ketones
Pawlu?, Piotr
experimental part, p. 10 - 13 (2012/06/04)
(E)-β-(Silyl)-α,β-unsaturated ketones have been efficiently synthesized via one-pot sequential ruthenium-catalyzed silylative homo-coupling of dimethylphenylvinylsilane or trimethylvinylsilane (Marciniec coupling) and rhodium-catalyzed selective desilylative acylation (Narasaka coupling) of (E)-1,2-bis(silyl)ethenes with acid anhydrides. Synthetic strategy relies on the selective mono-substitution of the bis(silyl)ethene intermediate.
Cu-catalyzed asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic β-silyl-α,β-unsaturated ketones. Synthesis of allylsilanes in high diastereo- and enantiomeric purity
Kacprzynski, Monica A.,Kazane, Stephanie A.,May, Tricia L.,Hoveyda, Amir H.
, p. 3187 - 3190 (2008/02/11)
A readily available and simple (MW = 444.5 g/mol) valine-based chiral phosphine is used to promote highly efficient catalytic asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic β-silyl-α, β-unsaturated ketones. The catalytic asy
Carbon-carbon bond-forming enantioselective synthesis of chiral organosilicon compounds by rhodium/chiral diene-catalyzed asymmetric 1,4-addition reaction
Shintani, Ryo,Okamoto, Kazuhiro,Hayashi, Tamio
, p. 4757 - 4759 (2007/10/03)
(Chemical Equation Presented) A new synthetic method for chiral organosilicon compounds through a rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to β-silyl α,β-unsaturated carbonyl compounds has been developed. By employing (R,R)-Bn-bod * as a ligand, a range of arylboronic acids can be coupled with these substrates in very high enantiomeric excess. The resulting β-silyl 1,4-adducts can be converted to β-hydroxy carbonyl compounds or allylsilanes while retaining their stereochemical information.
Reactions of phenyldimethylsilyllithium with β-N,N- dimethylaminoenones: A convenient synthesis of β-dimethyl(phenyl) silylacrylic acid and its derivatives
Fleming, Ian,Marangon, Elena,Roni, Chiara,Russell, Matthew G.,Chamudis, Sandra Taliansky
, p. 325 - 332 (2007/10/03)
Phenyldimethylsilyllithium reacted with 5,5-dimethyl-3-(N,N,-dimethylamino) cyclohex-2-enone (7), 3-(E)-N,N-dimethylaminopropenal (11), and 4-N,N-dimethylaminobut-3-en-2-one (13) to give the corresponding β-silyl-α,β-unsaturated carbonyl compounds 8, 12, and 14, in which the dimethylamino group has been displaced by the phenyldimethylsilyl group. Phenyldimethylsilyllithium reacted with ethyl β-N,N- dimethylaminopropenoate (15) by conjugate addition, but, in contrast to the ketones 7 and 13 and the aldehyde 11, the intermediate enolate 16 was C-protonated in the aqueous work-up to give ethyl 3-N,N-dimethylamino-3- dimethyl(phenyl)silylpropanoate (17). When the enolate 16 was instead given a mysteriously brief treatment with methyl iodide before work-up, the product was ethyl 3-(E)-dimethy(phenyl)silylpropenoate (18). Phenyllithium and methyllithium also added conjugatively to ethyl β-N,N-dimethylaminoacrylate (15) but, in contrast to the silyl case, the intermediate enolate 22 reacted unexceptionally with methyl iodide to give the products 25 and 26 of stereoselective C-methylation. This synthesis of the ester 18 was used to synthesize the Oppolzer sultam derivative 30.
Synthetic approach to the AB ring system of ouabain
Jung, Michael E.,Piizzi, Grazia
, p. 2572 - 2582 (2007/10/03)
Several novel hydroxylated cis-decalin derivatives, potential intermediates for the synthesis of the AB ring system of the important cardiotonic steroid ouabain, have been synthesized from commercially available starting materials. The first step in the preparation of these highly functionalized intermediates is a Robinson annulation of the β-keto ester 6 and the 4-silyl-3-buten-2-one 5 to furnish the octalone 4 with good diastereoselectivity in fair yield (due to competition with a novel silicon-to-carbon phenyl migration). Reduction of the epoxy alcohol 3 (derived from 4 in two high-yielding steps) with LiAlH4 gave a mixture of the desired triol 11 along with the product of an unusual reductive opening at the tertiary carbon, namely the triol 12. A plausible mechanism for this unusual reduction is presented as are possible methods for avoiding it. In particular, reduction of the corrresponding epoxy ketone 15 with aluminum amalgam proceeded in good yield to give the hydroxy ketone 16. Also reduction of the epoxide ester having the inverted stereochemistry at C3 afforded the desired tertiary alcohol 33 in good yield. Another approach using the β,γ-unsaturated ketal 38 permitted the formation of the tertiary alcohol 40. Fleming oxidation of the related, very functionalized silane 39 afforded the desired 1β-alcohol 41 in fair yield. Finally a novel rearrangement was observed when the epoxy alcohol 24 was treated with DIBAL to effect loss of the angular hydroxymethyl group to produce the tetrasubstitued alkene 29 in high yield.
Reactions of phenyldimethylsilyllithium with β-N,N-dimethylaminoenones
Fleming, Ian,Marangon, Elena,Roni, Chiara,Russell, Matthew G.,Chamudis, Sandra Taliansky
, p. 200 - 201 (2007/10/03)
Phenyldimethylsilyllithium reacts with the β-N,N-dimethylaminoenones 1 and 7, with the enal 5, and with ethyl β-N,N-dimethylaminoacrylate 9 to give the corresponding α,β-unsaturated carbonyl compounds with a β-phenyldimethylsilyl group, but in the last ca
Novel rearrangements of 4-silyl-3-buten-2-ones
Jung, Michael E.,Piizzi, Grazia
, p. 3911 - 3914 (2007/10/03)
Two-4-silyl-3-buten-2-ones, 2a, and 2c, underwent an interesting rearrangement involving migration of the allyl or phenyl group on the silicon atom to the adjacent enone carbon when treated with various bases.
Synthesis of vinylsilanes by silyl-cupration of acetylenes using tert-butyldiphenylsilyl-cuprate reagents
Barbero, Asuncion,Cuadrado, Purificacion,Fleming, Ian,Gonzalez, Ana M.,Pulido, Francisco,Sanchez, Alicia
, p. 1525 - 1532 (2007/10/02)
The tert-butyldiphenylsilyl-cuprate 2 reacts with acetylenes 1 and 5-10 to give vinyl-cuprates 3 and 11, which react with electrophiles to give the vinylsilanes 4 and 12-17 carrying the relatively hindered and hence unreactive tert-butyldiphenylsilyl group.In comparative tests, the tert-butyldiphenylsilyl group shows some properties that are usefully different from those of relatively unhindered silyl groups and others that are similar.
