80814-92-2Relevant academic research and scientific papers
Enantioselective, Catalytic Multicomponent Synthesis of Homoallylic Amines Enabled by Hydrogen-Bonding and Dispersive Interactions
Ronchi, Elisabetta,Paradine, Shauna M.,Jacobsen, Eric N.
supporting information, p. 7272 - 7278 (2021/05/26)
We report a one-step catalytic, enantioselective method for the preparation of homoallylic N-Boc amines directly from acetals. Reactive iminium ion intermediates are generated in situ through the combination of an acetal, a chiral thiourea catalyst, trialkylsilyl triflate, and N-Boc carbamate and are subsequently trapped by a variety of allylsilane nucleophiles. No homoallylic ether byproducts are detected, consistent with allylation of the iminium intermediate being highly favored over allylation of the intermediate oxocarbenium ion. Acetals derived from aromatic aldehydes possessing a variety of functional groups and substitution patterns yield homoallylic amines with excellent levels of enantiomeric enrichment. Experimental and computational data are consistent with an anchoring hydrogen-bond interaction between the protioiminium ion and the amide of the catalyst in the enantiodetermining transition state, and with stereodifferentiation achieved through specific noncovalent interactions (NCIs) with the catalyst pyrenyl moiety. Evidence is provided that the key NCI in the major pathway is a π-stacking interaction, contrasting with the cation-πinteractions invoked in previously studied reactions promoted by the same family of aryl-pyrrolidino-H-bond-donor catalysts.
Enantioselective Synthesis of α-Allyl Amino Esters via Hydrogen-Bond-Donor Catalysis
Bendelsmith, Andrew J.,Kim, Seohyun Chris,Wasa, Masayuki,Roche, Stéphane P.,Jacobsen, Eric N.
supporting information, p. 11414 - 11419 (2019/08/20)
We report a chiral-squaramide-catalyzed enantio- and diastereoselective synthesis of α-allyl amino esters. The optimized protocol provides access to N-carbamoyl-protected amino esters via nucleophilic allylation of readily accessible α-chloro glycinates. A variety of useful α-allyl amino esters were prepared, including crotylated products bearing vicinal stereocenters that are inaccessible through enolate alkylation, with high enantioselectivity (up to 97% ee) and diastereoselectivity (>10:1). The reactions display first-order kinetic dependence on both the α-chloro glycinate and the nucleophile, consistent with rate-limiting C-C bond formation. Computational analysis of the uncatalyzed reaction predicts an energetically inaccessible iminium intermediate, and a lower energy concerted SN2 mechanism.
Nickel catalyzed dealkoxylative Csp2-Csp3 cross coupling reactions - Stereospecific synthesis of allylsilanes from enol ethers
Guo, Lin,Leiendecker, Matthias,Hsiao, Chien-Chi,Baumann, Christoph,Rueping, Magnus
supporting information, p. 1937 - 1940 (2015/02/05)
The application of cyclic and acyclic enol ethers as electrophiles in cross coupling reactions offers new possibilities for the preparation of functional compounds. A novel nickel catalyzed dealkoxylative cross coupling reaction allows access to structurally diverse allylsilanes and alcohol derivatives with high stereospecificity and in good yields under mild reaction conditions directly from the corresponding enol ethers.
Catalyst-controlled regioselectivity in the synthesis of branched conjugated dienes via aerobic oxidative heck reactions
Zheng, Changwu,Wang, Dian,Stahl, Shannon S.
supporting information, p. 16496 - 16499,4 (2020/09/15)
Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl bromide and an alkene. DFT computational studies reveal that steric effects of the 2,9-dimethylphenanthroline ligand promote C-C bond formation at the internal position of the alkene.
Fluorination process
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Page/Page column 35-36, (2008/06/13)
Compounds of formula (II), (IIIa) or (IIIb) (variables are described in the specification) are prepared by fluorination of β,γ-unsaturated alkyl silanes. These compounds are useful as building blocks in the pharmaceutical industry.
AN EFFICIENT METHOD FOR CONVERSION OF CARBOXYLIC ACID DERIVATIVES TO ALLYLSILANES
Anderson, M. B.,Fuchs, P. L.
, p. 621 - 636 (2007/10/02)
Treatment of acid halides with trimethylsilylmethyl cerium dichloride affords bis β-silylethyl tertiary alcohols which efficiently undergo a trimethylchlorosilane-promoted Peterson reaction to generate allylsilanes in high overall yield.
THE CERIUM MEDIATED CONVERSION OF ESTERS TO ALLYLSILANES
Narayanan, B.A.,Bunnelle, W.H.
, p. 6261 - 6264 (2007/10/02)
Reaction of esters with the reagent prepared from CeCl3 and TMSCH2MgCl in THF, followed by deoxysilylation on silica gel, effects efficient conversion to allylsilanes.Methyl 1-adamantane carboxylate, a sterically hindered ester, does not react under these conditions.
