2406-22-6Relevant academic research and scientific papers
Synthesis and stereoselective evaluation of a (1R)-(–)-myrtenal-derived pseudo C2-symmetric dodecaheterocycle as a potential heterofunctional chiral auxiliary
Sánchez-Chávez, Anahí C.,Elena Vargas-Díaz, Ma.,Ontiveros-Rodríguez, Julio C.,Pérez-Estrada, Salvador,Flores-Bernal, Gustavo G.,Mendoza-Espinosa, Daniel,álvarez-Hernández, Alejandro,Delgado, Francisco,Tamariz, Joaquín,Gerardo Zepeda-Vallejo
, p. 4437 - 4441 (2018)
The synthesis and diastereoselective performance of the pseudo C2-symmetric dodecaheterocycle 3 in nucleophilic and electrophilic reactions are reported. Compound 3 proved to be a highly diastereoselective template to generate a pair of enantiomeric moieties within its structure in a programmed manner. Hence, this study describes the synthesis of a novel potential heterobifunctional chiral auxiliary.
The Bovine Serum Albumin-2-Phenylpropane-1,2-diolatodioxo-osmium(VI) Complex as an Enantioselective Catalyst for cis-Hydroxylation of Alkenes
Kokubo, Toshio,Sugimoto, Toyonari,Uchida, Toshio,Tanimoto, Shigeo,Okano, Masaya
, p. 769 - 770 (1983)
The 1:1 complex between an osmate ester and bovine serum albumin was found to be effective as an enantioselective catalyst in the cis-hydroxylation of alkenes, affording diols in up to 68percent e.e. and turnover of the catalyst with tert-butyl hydroperoxide.
Chiral-auxiliary-controlled diastereoselectivity in the epoxidation of enecarbamates with DMD and mCPBA
Adam, Waldemar,Bosio, Sara G.,Wolff, Barbara T.
, p. 819 - 822 (2003)
(Matrix presented) Chiral oxazolidinone-substituted enecarbamates 1 are epoxidized in a diastereoselectivity up to 93:7 for both DMD and mCPBA. The diastereofacial differentiation depends on the steric interaction between the R1 substituent on the oxazolidinone ring and the incoming electrophile. The stereochemical course of epoxidation was assessed by chemical correlation with the known optically active diols.
New 2-acyl-1,3-dioxane derivatives from (1R)-(-)-myrtenal: stereochemical effect on their relative ability as chiral auxiliaries
Becerra-Martinez, Elvia,Velazquez-Ponce, Pedro,Sanchez-Aguilar, Miguel A.,Rodriguez-Hosteguin, Alfredo,Joseph-Nathan, Pedro,Tamariz, Joaquin,Zepeda, L. Gerardo
, p. 2727 - 2737 (2007)
Four 3,10-pinanediol derivatives 1a-d, prepared in 50-72% global yields from (1R)-(-)-myrtenal 2, were treated with (RO)2CHCOR3 (R3 = CH3, Ph) to afford 2-acyl-1,3-dioxanes 3a-f. The latter were submitted to nucleophilic additions using several Grignard reagents to mainly afford carbinols generated by re diastereofacial attack (85-99% yield, ≥88:12 dr). The lowest diastereoselectivity was observed when PhLi or hydrides were used as nucleophiles. Only an equatorial substituent at C-3 modifies the diastereoselectivity of the nucleophilic additions.
An improved version of the Sharpless asymmetric dihydroxylation
Mehltretter,Dobler,Sundermeier,Beller
, p. 8083 - 8087 (2000)
The osmium catalyzed asymmetric dihydroxylation of olefins (Sharpless AD) was studied under controlled pH conditions. It was found that providing a constant pH value of 12.0 leads to improved reaction rates for internal olefins. Hydrolysis aids such as methanesulfonamide can be omitted. For terminal olefins, working at a constant pH of 10.0 at room temperature leads to higher enantioselectivities compared to AD reactions without pH control. (C) 2000 Elsevier Science Ltd.
Catalytic asymmetric dihydroxylation of α-methylstyrene by air
Krief, Alain,Colaux-Castillo, Catherine
, p. 4189 - 4192 (1999)
Dioxygen is able, under visible irradiation, to promote the high yielding and highly asymmetric dihydroxylation of α-methylstyrene in the presence of catalytic amounts of Os(VI), phthalazine dihydroquinidine chiral ligand [(DHQD)2PHAL].
Absolute stereochemical determination of 1,2-diols via complexation with dinaphthyl borinic acid
Torabi Kohlbouni, Saeedeh,Sarkar, Aritra,Zhang, Jun,Li, Xiaoyong,Borhan, Babak
supporting information, p. 817 - 823 (2020/03/26)
Rapid derivatization of chiral 1,2-diols with dinaphthyl borinic acid (DBA) leads to a cyclic boronate, enabling the absolute stereochemical prediction via exciton-coupled circular dichroic (ECCD) of the naphthyl groups. Aryl- and alkyl-substituted 1,2-diols derivatized with DBA yield a predictable ECCD, which is also in agreement with theoretical predictions derived from computationally minimized structures.
Racemic or enantioselective osmium-catalyzed dihydroxylation of olefins under near-neutral conditions
Blumberg, Shawn,Martin, Stephen F.
, p. 7 - 14 (2020/10/08)
K3Fe(CN)6 and NaIO4 serve as catalytic co-oxidants for osmium-catalyzed dihydroxylations that are performed under near-neutral conditions with K2S2O8 as the stoichiometric oxidant and Na2HPO4 as the base. By using either quinuclidine or hydroquinidine 1,4-phthalazinediyl ether [(DHQD)2Phal], good yields of racemic or enantioenriched diols are obtained. This simple, biphasic procedure offers advantages over other neutral dihydroxylation protocols that use N-methylmorpholine oxide as the stoichiometric oxidant, by suppressing the secondary catalytic cycle that leads to reduced enantioselectivities. The utility of the procedure, which is nicely suited for base-labile starting materials or products, is demonstrated by performing the dihydroxylation in the presence of an aliphatic aldehyde moiety.
Syn-dihydroxylation of alkenes using a sterically demanding cyclic diacyl peroxide
Pilevar, Afsaneh,Hosseini, Abolfazl,Becker, Jonathan,Schreiner, Peter R.
, p. 12377 - 12386 (2019/10/11)
The syn-dihydroxylation of alkenes is a highly valuable reaction in organic synthesis. Cyclic acyl peroxides (CAPs) have emerged recently as promising candidates to replace the commonly employed toxic metals for this purpose. Here, we demonstrate that the structurally demanding cyclic peroxide spiro[bicyclo[2.2.1]heptane-2,4′-[1,2]dioxolane]-3′,5′-dione (P4) can be effectively used for the syn-dihydroxylation of alkenes. Reagent P4 also shows an improved selectivity for dihydroxylation of alkenes bearing β-hydrogens as compared to other CAPs, where both diol and allyl alcohol products compete with each other. Furthermore, the use of enantiopure P4 (labeled P4′) demonstrates the potential of P4′ for a metal-free asymmetric syn-dihydroxylation of alkenes.
Ligand-Controlled Regiodivergent Enantioselective Rhodium-Catalyzed Alkene Hydroboration
Bochat, Andrew J.,Shoba, Veronika M.,Takacs, James M.
, p. 9434 - 9438 (2019/06/27)
Regiocontrol in the rhodium-catalyzed boration of vinyl arenes is typically dominated by the presence of the conjugated aryl substituent. However, small differences in TADDOL-derived chiral monophosphite ligands can override this effect and direct rhodium-catalyzed hydroboration of β-aryl and β-heteroaryl methylidenes by pinacolborane to selectively produce either chiral primary or tertiary borated products. The regiodivergent behavior is coupled with enantiodivergent addition of the borane. The nature of the TADDOL backbone substituents and that of the phosphite moiety function synergistically to direct the sense and extent of regioselectivity and enantioinduction. Twenty substrates are shown to undergo each reaction mode with regioselectivity values reaching greater than 20:1 and enantiomer ratios reaching up to 98:2. A variety of subsequent transformations illustrate the potential utility of each product.
