698378-72-2Relevant academic research and scientific papers
Highly Selective Addition of a Broad Spectrum of Trimethylsilane Pro-nucleophiles to N-tert-Butanesulfinyl Imines
Das, Manas,O'Shea, Donal F.
, p. 18717 - 18723 (2016/01/25)
Addition of organotrimethylsilane reagents to chiral N-tert-butanesulfinyl imines can be achieved in good yields and with excellent diastereoselectivities by employing TMSO-/Bu4N+ as a Lewis base activator in THF. A variety of aliphatic, aromatic, heteroaromatic and organometallic chiral imines were utilised as electrophiles for the synthesis of enantioenriched N-tert-butanesulfinyl amides. Remarkably, the same sets of reaction conditions could be used with a highly diverse range of bench-stable organotrimethylsilane reagents, which highlights the generality and robustness of this methodology. Addition of organotrimethylsilane reagents to chiral N-tert-butanesulfinyl imines can be achieved in good yields and with excellent diastereoselectivities by employing TMSO-/Bu4N+ as a Lewis base activator in THF. A variety of aliphatic, aromatic, heteroaromatic and organometallic chiral imines were utilised as electrophiles for the synthesis of enantioenriched N-tert-butanesulfinyl amides, highlighting the generality and robustness of this methodology.
Enantioselective synthesis of angularly substituted 1-azabicylic rings: Coupled dynamic kinetic epimerization and chirality transfer
Aron, Zachary D.,Ito, Tatsuya,May, Tricia L.,Overman, Larry E.,Wang, Jocelyn
, p. 9929 - 9948 (2013/10/22)
A new strategy for enantioselective synthesis of azacyclic molecules in which dynamic kinetic equilibration of diastereomeric iminium ions precedes a stereochemistry-determining sigmatropic rearrangement is reported. The method is illustrated by the synthesis, in high enantiomeric purity (generally 95-99% ee), of a variety of 1-azabicyclic molecules containing angular allyl or 3-substituted 2-propenyl side chains adjacent to nitrogen and up to three stereogenic centers. In these products, the size of the carbocyclic ring is varied widely (5-12 membered); however, useful yields are obtained in forming 1-azabicyclic products containing only fused pyrrolidine and piperidine rings. Chirality transfer from substituents at carbons 1 and 2 of the 3-butenylamine fragment of the starting material is investigated, with methyl and phenyl substituents at the allylic position shown to provide exquisite stereocontrol (generally 98-99% chirality transfer). An attractive feature of the method is the ability to carry out the key transformation in the absence of solvent. Illustrated also is the high yielding conversion of four such products to a new family of bicyclic β-amino acids of high enantiomeric purity.
Direct catalytic asymmetric aminoallylation of aldehydes: Synergism of chiral and nonchiral Bronsted acids
Ren, Hong,Wulff, William D.
supporting information; experimental part, p. 5656 - 5659 (2011/06/18)
The development of a catalytic asymmetric method for the direct aminoallylation of aldehydes is described that gives high asymmetric inductions for a broad range of substrates including both aromatic and aliphatic aldehydes. This method allows for direct isolation of unprotected analytically pure homoallylic amines without chromatography. The unique catalyst system developed for this process involves the synergistic interaction between a chiral and a nonchiral Bronsted acid.
N-propargylamides via the asymmetric Michael addition of B-alkynyl-10-TMS-9-borabicyclo[3.3.2]decanes to N-acylimines
Gonzalez, Ana Z.,Canales, Eda,Soderquist, John A.
, p. 3331 - 3334 (2007/10/03)
The asymmetric synthesis of N-propargylamides through Michael addition of the alkynylborane 1 to N-acylimines is reported. The N-acetylimines provide the best substrates for the process exhibiting high selectivity (56-95% ee) with predictable stereochemis
Highly diastereoselective and enantioselective preparation of homoallylic amines: Application for the synthesis of β-amino acids and γ-lactams
Ramachandran, P. Veeraraghavan,Burghardt, Thomas E.
, p. 4387 - 4395 (2007/10/03)
Reactions of N-silyl- and N-aluminoimines with B- allyldiisopinocampheylborane in the presence of methanol, followed by oxidative workup furnished homoallylic amines in good yields and high ee. A 11B NMR spectroscopy study revealed that the reactions do not proceed, even at room temperature, unless a molar equivalent of water or methanol is added. The first reagent-controlled asymmetric crotylboration and alkoxyallylboration of aldimines furnishing β-methyl or βalkoxy homoallylic amines in very high diastereoselectivity and enantioselectivity are reported herein. Crotylboration and alkoxyallylboration of imines proceed only with the "allyl"-boron "ate" complexes, instead of the "allyl"-dialkylboron reagents used with aldehydes. The addition of methanol is necessary for these reactions as well. Application of this methodology for the conversion of representative nitriles to β-amino acids in two steps has been described. Additionally, a procedure for the preparation of chiral δ-amino alcohols and γ-lactams from nitriles is also reported.
Synthesis of enantiopure 1-aryl-1-butylamines and 1-aryl-3-butenylamines by diastereoselective addition of allylzinc bromide to imines derived from (R)-phenylglycine amide
Dalmolen, Jan,Van Der Sluis, Marcel,Nieuwenhuijzen, Jose W.,Meetsma, Auke,De Lange, Ben,Kaptein, Bernard,Kellogg, Richard M.,Broxterman, Quirinus B.
, p. 1544 - 1557 (2007/10/03)
The synthesis of enantiopure 1-aryl-1-butylamines via a highly diastereoselective addition of allylzinc bromide to imines derived from (R)-phenylglycine amide is reported. These are synthesised by a three-step procedure, which involves: (a) formation of the chiral imines; (b) asymmetric addition of the allylzinc reagent; (c) removal of the chiral auxiliary by means of a reductive or non-reductive method. The reductive method provides 1-aryl-1-butylamines whereas the non-reductive method preserves the double bond to afford 1-aryl-3-butenylamines. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
