106296-60-0Relevant academic research and scientific papers
Iridium-catalyzed allylation of chiral β-stereogenic alcohols: Bypassing discrete formation of epimerizable aldehydes
Schmitt, Daniel C.,Dechert-Schmitt, Anne-Marie R.,Krische, Michael J.
supporting information, p. 6302 - 6305 (2013/02/25)
The cyclometalated π-allyliridium 3,4-dinitro-C,O-benzoate complex modified by (R)- or (S)-Cl,MeO-BIPHEP promotes the transfer hydrogenative coupling of allyl acetate to β-stereogenic alcohols with good to excellent levels of catalyst-directed diastereose
Stereoselective total synthesis of arenastatin A, a spongean cytotoxic depsipeptide
Kotoku, Naoyuki,Narumi, Fuminori,Kato, Tomoya,Yamaguchi, Miho,Kobayashi, Motomasa
, p. 7147 - 7150 (2008/03/11)
A highly stereoselective total synthesis of arenastatin A, an extremely potent cytotoxic cyclic depsipeptide from marine sponge, was developed. The desired 7,8-β-epoxide in arenastatin A was constructed by asymmetric sulfur ylide-mediated epoxidation in g
Tetrafibricin: Synthesis of the C1-C13, C15-C25, and C27-C40 fragments
Bouzbouz, Samir,Cossy, Janine
, p. 3469 - 3472 (2007/10/03)
(Chemical Equation Presented) A sequence of chemoselective cross-metathesis reactions and enantioselective allyltitanations of aldehydes has been used to prepare the C1-C13, C15-C26, and C27-C40 fragments of tetrafibricin.
N,N'-Bis(2,2,2-trifluoroethyl)-N,N'-ethylenetartramide: An Improved Chiral Auxiliary for the Asymmetric Allylboration Reaction
Roush, William R.,Grover, Paul T.
, p. 3806 - 3813 (2007/10/02)
N,N'-Bis(2,2,2-trifluoroethyl)-N,N'-ethylenetartramide (8), synthesized by a simple four-step sequence from ethylenediamine and benzylidenetartaric acid, was designed in anticipation that the derived allylboronates 9-11 would display enhanced reactivity o
Two Routes to Chiral Dithianes, Useful Synthons for the Preparation of Functionalised Spiroketals
Kermadec, Dominique de,Prudhomme, Michelle
, p. 7335 - 7336 (2007/10/02)
Two routes are described leading to chiral precursors for the synthesis of new substituted spiroketals.The stabilities of the methoxymethyl, tert-butyldimethylsilyl and tert-butyldiphenylsilyl hydroxyl protecting groups were tested in these reaction seque
Asymmetric Synthesis Using Tartrate Ester Modified Allylboronates. 2. Single and Double Asymmetric Reactions with Alkoxy-Substituted Aldehydes
Roush, William R.,Hoong, Lee K.,Palmer, Michelle A. J.,Straub, Julie A.,Palkowitz, Alan D.
, p. 4117 - 4126 (2007/10/02)
The reactions of tartrate allylboronates 1a and 1b with a series of chiral and achiral alkoxy-substituted aldehydes are described.It is shown that conformationally unrestricted α- and β-alkoxy aldehyde substituents have a significant, negative impact on the stereoselectivity of the asymmetric allylborations.For example, α-alkoxy aldehydes 25-27 and β-alkoxy aldehydes 28-30 undergo asymmetric allylborations with 1 in only 56-59percent and 63-66percent ee, respectively, while the reactions of 1 and aliphatic aldehydes such as decanal or cyclohexane-carboxaldehyde proceed in 86-87percent ee under the same conditions.Evidence of reduced stereoselection is also apparent in the double diastereoselectivity data reported in Table I and Scheme I for the asymmetric allylborations of chiral β-alkoxy aldehydes 16 and 19 and chiral α-alkoxy aldehyde 22.In contrast, chiral aldehydes containing alkoxy groups that are conformationally constrained by incorporation in rings, as in glyceraldehyde acetonide 4,4-deoxythreose ketal 7, and α,β-epoxy aldehydes 10 and 13, are excellent allylboration substrates, with diastereoselection in the cases of 4 and 7 being significantly greater than that obtained with simpler achiral substrates.A model that rationalizes this "alkoxy effect" is presented.Specifically, it is inferred that the observed trends in stereoselection are not steric in origin, but rather that unfavorable lon pair/lone pair interactions occur between the tartrate ester carbonyl and alkoxy substituents particularly of conformationally unconstrained aldehyde substrates (e.g., 16, 19, 22, 25-30) that results in diminished reaction stereoselection (see transition structures 58 and 61).For substrates with conformationally constrained alkoxy substituents , e.g. 4 and 7, favorable lone pair/dipole interactions between the tartrate ester carbonyl and the backside of the β-alkoxy C-O bond leads to increased stabilization of the favored transition state (see transition structures 59 and 60) and hence to increased reaction diastereoselection.A simple method for the analysis of the average diastereofacial selectivity of a chiral reagent in a pair of double asymmetric reactions is also presented.This analysis, which is independent of the intrinsic diastereofacial bias of the chiral aldehyde, enables one to make direct comparisons of the relative diastereoselectivities of a range of chiral substrates with a given chiral reagent (or vice versa).In this way, double diastereoselcetivity data are easily analyzed to determine if the chiral reagent/chiral substrate pair is "well behaved" compared to typical achiral substrate reference systems, thereby providing insight into the structural features that influence reaction stereoselectivity.
