58407-67-3Relevant academic research and scientific papers
Enantiomerically Enriched α-Borylzinc Reagents by Nickel-Catalyzed Carbozincation of Vinylboronic Esters
Chen, Jingjia,Hu, Weipeng,Jin, Jing,Lovinger, Gabriel J.,Morken, James P.,Zhang, Chenlong
supporting information, p. 14189 - 14195 (2021/09/11)
In this paper is described a synthesis of enantiomerically enriched, configurationally stable organozinc reagents by catalytic enantioselective carbozincation of a vinylboronic ester. This process furnishes enantiomerically enriched α-borylzinc intermediates that are shown to undergo stereospecific reactions, producing enantioenriched secondary boronic ester products. The properties of the intermediate α-borylzinc reagent are probed and the synthetic utility of the products is demonstrated by application to the synthesis of (-)-aphanorphine and (-)-enterolactone.
Efficient Control of the Stereoselectivity in Reactions of 2-Oxy-Substituted Benzylic Radicals
Moufid, Nadira,Renaud, Philippe,Hassler, Carla,Giese, Bernd
, p. 1006 - 1012 (2007/10/02)
The stereoselectivity in reactions of 2-oxy-substituted radicals of type B was investigated.As expected, minimization of allylic 1,3-starin was the major controlling factor.Under standard conditions, only a modest level of stereoselectivity was observed.E
Weak Base Promoted β-Elimination Reactions in 1-Phenyl-1-propyl Derivatives. Evidence for an Intermediate in the E2C Reaction
Kwart, Harold,Wilk, Kazimiera A.
, p. 3038 - 3041 (2007/10/02)
We describe the observation of a nucleophile trigger mechanism in the case of the weak base promoted β-elimination (E2C process) and suggest permutational isomerism of TBP intermediates.Weak bases, namely, bromide and fluoride ions, bring about elimination in a bent transition state to which only a small fraction of a covalent bond to the nucleophile-base and some leaving group departure must be achieved in an orienting intermediate.These studies provide evidence for a TBP structure surrounding C-α in the 1-phenyl-1-propyl system and attribute the equal availability of abstractable H and D of both diastereoisomers to the action of the promoter bases.
CONFORMATIONAL ANALYSIS OF AMPHETAMINE IN SOLUTION BASED ON UNAMBIGUOUS ASSIGNMENT OF THE DIASTEREOTOPIC BENZYLIC PROTONS IN THE (1)H NMR SPECTRA
Makriyannis, Alexandros,Knittel, James
, p. 4631 - 4634 (2007/10/02)
The erythro- and threo-amphetamine-β-d diastereomers were synthesized and used for the unambiguous assignment of the diastereotopic benzylic protons and the mesurement of vicinal (1)H-(1)H coupling constants which were used to determine the distribution of rotamers around the central Cα-Cβ bond in the side chain.
THE EFFECT OF PHENYL SUBSTITUENTS ON ELIMINATION STEREOCHEMISTRY: A MECHANISTIC MANIFOLD IN ALKOXIDE PROMOTED DECOMPOSITION OF 1-PHENYL-1-PROPYLTRIMETHYLAMMONIUM ION
Machkova, Zuzana,Zavada, Jiri
, p. 833 - 849 (2007/10/02)
Reactions of the positionally isomeric 1-phenyl-1-propyl (I) and 1-phenyl-2-propyltrimethylammonium (II) ions with CH3OK - CH3OH, t-C4H9OK - t-C4H9OH and t-C4H9OK - C6H6 systems have been investigated with aid of the deuterated analogues erythro-2-D-I, threo-2-D-I, 1-D-I and threo-1-D-II.At least five mechanistic components (anti-β-elimination, syn-β-elimination, α',β-elimination, Sommelet-Hauser rearrangement and SN2 substitution) have been found to participate in the reaction of the quaternary compound I, in proportions varying greatly with base-solvent combination.The corresponding reactions of the isomeric compound II proceeded in a more simple manner, withount the intervention of ylide pathways in the olefin as well as in the amine formation.The stereochemistry of β-elimination determined for the two phenyl-substituted 'onium compounds has been compared with that reported previously for structurally related aliphatic analogues.The "anomalously" low propensity for syn-elimination as well as the "anomalously" high values of trans/cis-olefin rations in anti-elimination stigmatizing the presence of phenyl substituents are proposed to originate from a lack of base-approach hindrance in the reaction.
