51752-50-2

Upstream product

• 100-42-5 styrene 
• 74-85-1 ethene 
• 79238-94-1 3-methyl-2-phenyl-1-trimethylsilylpentan-3-ol 
• 20883-16-3 β-methylcinnamyl acetate 
• 925-90-6 ethylmagnesium bromide 
• 2039-93-2 1-ethylstyrene 
• 39171-59-0 (4-bromobut-2-en-2-yl)benzene 
• 557-20-0 diethylzinc 
• 54976-38-4 (E)-3-phenylbut-2-en-1-ol 
• 79239-00-2 2-phenyl-3-trimethylsilylmethylpentan-2-ol 

Relevant academic research and scientific papers

Triarylphosphine ligands with hemilabile alkoxy groups: Ligands for nickel(II)-catalyzed olefin dimerization reactions. hydrovinylation of vinylarenes, 1,3-dienes, and cycloisomerization of 1,6-dienes

Substitution of one of the phenyl groups of triphenylphosphine with a 2-benzyloxy-, 2-benzyloxymethyl- or 2-benzyloxyethyl-phenyl moiety results in a set of simple ligands, which exhibit strikingly different behaviour in various nickel(II)-catalyzed olefin dimerization reactions. Complexes of ligands with 2-benzyloxyphenyl- and 2-benzyloxymethylphenyldiphenylphosphine (L5 and L6, respectively) are most active for hydrovinylation (HV) of vinylarenes, with the former leading to extensive isomerization of the primary 3-aryl-1-butenes into the conjugated 2-aryl-2-butenes even at -55 °C. However, 2-benzyloxymethyl-substituted ligand L6 is slightly less active, affording up to quantitative yields of the primary products of HV at ambient temperature with no trace of isomerization, thus providing the best option for a practical synthesis of these compounds. In sharp contrast, hydrovinylation of a variety of 1,3-dienes is best catalyzed by nickel(II) complexes of 2- benzyloxyphenyldiphenylphosphine, L5. The other two ligands, 2-benzyloxymethyl- (L6) and 2-benzyloxyethyldiphenylphosphine (L7) are much less effective in the HV of 1,3-dienes. Nickel(II)-catalyzed cycloisomerization of 1,6-dienes into methylenecyclopentanes, a reaction mechanistically related to the other hydrovinylation reactions, is also uniquely effected by nickel(II) complexes of L5, but not of L6 or L7. In an attempt to prepare authentic samples of the methylencyclohexane products, nickel(II) complexes of N-heterocyclic carbene ligands were examined. In sharp contrast to the phosphines, which give the methylenecyclopentanes, methylenecyclohexanes are the major products in the (N-heterocyclic carbene)nickel(II)-mediated reactions.

Short synthesis of chiral 4-substituted (S)-imidazolinium salts bearing sulfonates and their use in γ-selective reactions of allylic halides with grignard reagents

A one-pot reaction of Boc-protected amino alcohols and 2-sulfobenzoic anhydride followed by the addition of a wide variety of primary amines has allowed rapid access to diverse libraries of amidosulfonates 1,2-C 6H4(SO3su

Stereogenic-at-metal Zn- and Al-based N-Heterocyclic Carbene (NHC) complexes as bifunctional catalysts in Cu-free enantioselective allylic alkylations

Investigations detailed herein demonstrate the ability of chiral bidentate N-heterocyclic carbenes to promote directly - without the need for a Cu salt - site- and enantioselective C-C bond forming reactions. Within this context, catalytic allylic alkylat

Catalytic asymmetric synthesis using feedstocks: An enantioselective route to 2-arylpropionic acids and 1-arylethyl amines via hydrovinylation of vinyl arenes

A three-step procedure for the synthesis of 2-arylpropionic acids (profens) from vinyl arenes in nearly enantiomerically pure form has been developed. Excellent yields (>97%), regioselectivities (>99%), and enantioselectivities (>97% ee) for the desired branched products were obtained in the asymmetric hydrovinylation reactions of vinyl arenes, and the products from these reactions were transformed into 2-arylpropionic acids via oxidative degradation. Subsequent Curtius or Schmidt rearrangements of these acids provided highly valued 1-arylethyl amines, including a prototypical primary amine with an α-chiral tertiary N-alkyl group, in very good yields.

Tunable phosphoramidite ligands for asymmetric hydrovinylation: Ligands par excellence for generation of all-carbon quaternary centers

α-Alkylstyrenes undergo efficient hydrovinylation (addition of ethene) in the presence of a nickel catalyst prepared from [(allyl)NiBr] 2, Na+[BAr4]- [Ar = 3,5-bis(trifluoromethyl)phenyl], and a phosphoramidite ligand giving products in excellent yields and enantioselectivities. In many cases phosphoramidites derived from achiral 2,2′-biphenol are almost as good as ligands derived from the more expensive enantiopure 1,1′-bi(2-naphthol)s. The hydrovinylation products, which carry two versatile latent functionalities, an aryl and a vinyl group, are potentially useful for the synthesis of several important natural products containing benzylic all-carbon quaternary centers. Georg Thieme Verlag Stuttgart.

Efficient, selective, and green: Catalyst tuning for highly enatioselective reactions of ethylene

Fine tuning of the biaryl and amino moieties of Feringa's phosphoramidite ligands yields structurally simpler, yet more efficient and selective, ligands for asymmetric hydrovinylation of vinylarenes and acylic 1,3-dienes. The enantioselectivities and yields observed in the formation of the 3-arylbutenes are among the highest for all asymmetric catalytic processes reported to date for the synthesis of intermediates for the widely used antiinflammatory 2-arylpropionic acids including naproxen, ibuprofen, fenoprofen, and flurbiprofen.

Studies of the formation of all-carbon quaternary centres, en route to lyngbyatoxin A. A comparison of phenyl and 7-substituted indole systems.

Copper mediated allylic substitutions and conjugate additions to geranyl, cinnamyl and allylic indole compounds have been investigated with the aim of finding a method for the creation of the all-carbon quaternary centre present in the natural product lyngbyatoxin A. Reaction conditions have been found giving a 68% SN2' selectivity in the copper mediated addition of PhMgBr to geranyl chloride, as well as 99% and 95% SN2' selectivity in the copper catalysed addition of EtMgBr to cinnamyl chloride and acetate, respectively. When the optimised reaction conditions were applied to the corresponding allylic compounds containing a 7-substituted indole moiety, the regioselectivity was reversed giving only the SN2 product. The allylic indole-containing substrates were also found to be unproductive in Pd- or Mo-catalysed SN2'-type substitution reactions. In related studies, copper catalysed conjugate addition of EtMgBr to the tricyclic lactam 6-methyl-pyrrolo[3,2,1-ij]quinolin-4-one gave a maximum of 20% of the 1,4-addition product.

Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group

γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.

CARBONIUM ION REARRANGEMENTS CONTROLLED BY THE PRESENCE OF A SILYL GROUP

Tertiary alcohols with a γ-silyl group (3) generally undergo a simple carbonium ion rearrangement in acid giving a single alkene product (4) with loss of the silyl group.