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1,2-Amino alcohols from 1,2-diols

Kobayashi et al. developed chiral Lewis acids derived from A -benzyldiphenylproli-nol and boron tribromide and used these successfully as catalysts in enantioselective Diels-Alder reactions [89]. The corresponding polymeric catalyst 71 was prepared and used for the Diels-Alder reaction of cyclopentadiene with methacrolein [90]. Different polymeric catalysts 72, 73, 74 were prepared from supported chiral amino alcohols and diols fimctionalized with boron, aluminum and titanium [88,90]. In these polymers copolymerization of styrene with a chiral auxiliary containing two polymerizable groups is a new approach to the preparation of crosslinked chiral polymeric ligands. This chiral monomer unit acts as chiral ligand and as a crosslink. [Pg.967]

Interconversion of a thioxocarboxylic ester with an alcohol can be achieved in the presence of a base. The reaction takes place with high yields if amino alcohols or diols are used. A series of macro-cyclic polyether thioxoesters has been prepared by treating (9,(9 -diethyl dithiooxalate and 0,0 -dimethyl 2,6-pyridinedicarbothioate with glycols. Methanol or ethanol were removed from the equilibrium mixture by distillation or adsorption in molecular sieves (equation 48). ... [Pg.449]

The structure and stereochemistry of the saturated pyrrolizidinediols have been studied by Culvenor and his collaborators. The structures of the readily available isomers platynecine (1) and dihydroxyheliotridane (2) have been thoroughly established earlier, but hitherto the remaining diols obtained by hydrolysis of alkaloids have been too inaccessible for detailed study. These include hastanecine from the alkaloid hastacine, turneforcidine from turnefor-cine, macronecine from macrophylline, and an unnamed amino-alcohol from retusine. [Pg.59]

Cyclic Amines from Amino Alcohols or Diols... [Pg.252]

In 2013, Oe and co-workers achieved the first enantioselective synthesis of p-amino alcohols from the reaction of 1,2-diols and secondary amines catalyzed by [Ru(p-cymene)Cl2]2/(5,/ )-JOSIPHOS with moderate enantioselectivity (Eq. 55) [177]. [Pg.337]

Eka Putra A, Oe Y, Ohta T (2013) Ruthenium-catalyzed enantioselective synthesis of P-amino alcohols from 1,2-diols by IxHTOwing hydrogen . Eur J Org Chem 2013(27) 6146-6151... [Pg.368]

Scheme 12.42 I rolidine or piperidine synthesis from amino alcohols or diols. Scheme 12.42 I rolidine or piperidine synthesis from amino alcohols or diols.
Miller s biomimetic approach inspired Ishihara [234] to develop a minimal artificial acylase for the KR of mono-protected cw-l,2-diols and A-acylated 1,2-amino alcohols. Derived from (S)-histidine, Ishihara s organocatalyst contains only one stereogenic centre and incorporates a sulfonamide linkage in place of a polypeptide chain to allow the NH group to engage as an H-bond donor with the substrates (Fig. 13) [234]. [Pg.261]

Hydroxy acids provide characteristic mono or diol synthons whereas amino acids are the natural source for 1,2-amino alcohol fragments. A stereogenic center in either configuration, with methyl brandling, may be obtained from (S)-3-hydroxy-2-methylpropanoic acid, whereas quaternary dimethyl-substituted carbons with adjacent stereogenic centers are available from the degradation of camphor or a-pincnc. [Pg.106]

Phthalimidoglutaric acid (18), readily prepared from glutamic acid and phthalic anhydride, has served as a precursor for the preparation of several interesting condensation polymers (76MI1110l). For example, it is readily transformed (Scheme 7) into diisocyanate (19), which was utilized for the preparation of a number of optically active polyureas (by reaction with diamines), polyurethanes (by reaction with diols) and polyurea-urethanes (by reaction with amino alcohols). [Pg.273]

Borane and aluminum hydrides modified by chiral diols or amino alcohols are well-known, effective reagents for the stoichiometric enan-tioselective reduction of prochiral ketones and related compounds (34). Reduction of prochiral aromatic ketones with the Itsuno reagent, which is prepared from a chiral, sterically congested /3-amino alcohol and borane, yields the corresponding secondary alcohols in 94-100% ee... [Pg.270]

Amino-1 J-diols.1 This reagent can be used as an equivalent of NH3 in a synthesis of 2-amino-l,3-diols from chiral 2,3-epoxy alcohols. Thus reaction of the... [Pg.30]

From oxidative cleavage of 1,2-diols and 1,2-amino alcohols Dibutyltin oxide, 95 By reaction of alkyl halides with sulfur-stabilized carbanions Methylthiomethyl p-tolyl sulfone, 192 From reduction of carboxylic acids Vilsmeier reagent, 341 From terminal alkenes by addition reactions... [Pg.378]

Organomanganese(II) iodides, 210 Organotin reagents, 211 Organovanadium reagents, 219 From carboxylic acids Benzylchlorobis(triphenylphos-phine)palladium(II), 30 From other acyl derivatives Lithium o-lithiophenoxide, 166 Organomanganese(II) iodides, 210 From 1,2-diols or 1,2-amino alcohols Diethoxy triphenylphosphorane, 109... [Pg.393]

Fuji and co-workers have demonstrated the use of a PPY derivative that utilizes remote stereochemistry and an interesting induced fit process to control selectivity [21]. Upon acylation of catalyst 20, a conformational change occurs, stabilizing the intermediate N-acyliminium ion 21 (Fig. 2a,b). Chemical shifts in the XH NMR and nOes observed support a Jt-Jt interaction between the electron-rich naphthyl ring and the electron-deficient pyridinium ring. This blocks the top face of the catalyst and directs attack of the alcohol from the bottom face. Catalyst 20 effects resolutions of diol-monoesters and amino alcohol derivatives such as 22 and 23 with moderate to good selectivity factors (fcrei=4.7-21, see Fig. 2c) [22]. [Pg.193]

In the same vein as the cyclic sulfate activation of diols, cyclic sulfamidates have been prepared from 1,2- and 1,3-amino alcohols for the purpose of activating the carbinol toward nucleophilic attack [85-88]. (S)-Prolinol [85], A-benzyl serine t-butyl ester [86], and 2-(2-hy-... [Pg.389]

Unsymmetrical secondary and tertiary amines. Unsymmetrical amines are obtained in 50-95% yield by reaction of an alcohol and amine in the presence of this ruthenium catalyst. The intramolecular version of this reaction provides an efficient synthesis of cyclic amines either from oc,a>-amino alcohols and an alcohol or from a,tu-diols and an amine. The cyclization is useful for preparation of tetrahydroiso-quinolines.3... [Pg.434]

The DMAP derivative 19a was tested for kinetic resolution of a variety of mono esters of cyclic cis diols (rac-20a-i) (Scheme 12.5) [15]. Catalyst 19a afforded selectivity factors up to 12.3 and highly enantioenriched mono esters 20 with conversions of 65-73%. For this type of reaction the selectivity of the Campbell catalyst 19b was similar (selectivity factor 13.2, Scheme 12.5) [16a], The latter catalyst was identified by screening of a 31-mer library prepared from the parent N-(4-pyridyl)-a-methylproline and a variety of amines [16a], The solid-phase-bound forms of N-(4-pyridyl)-a-methylproline, as reported by Anson et al. [16b], are easily recyclable acylation catalysts affording selectivity factors up to 11.9 in the kinetic resolution of the secondary alcohol rac-20b (Scheme 12.5). In the kinetic resolution of N-acylated amino alcohols, selectivity factors up to 21 were achieved by use of the Kawabata-Fuji catalyst 19a, and up to 18.8 by use of the Campbell system 19b (Scheme 12.5) [15, 16a]. [Pg.327]


See other pages where 1,2-Amino alcohols from 1,2-diols is mentioned: [Pg.329]    [Pg.1209]    [Pg.24]    [Pg.404]    [Pg.266]    [Pg.175]    [Pg.1109]    [Pg.1224]    [Pg.212]    [Pg.459]    [Pg.105]    [Pg.224]    [Pg.243]    [Pg.850]    [Pg.145]    [Pg.220]    [Pg.71]    [Pg.9]    [Pg.339]    [Pg.344]    [Pg.430]    [Pg.618]    [Pg.262]    [Pg.85]    [Pg.324]    [Pg.151]    [Pg.516]    [Pg.374]    [Pg.47]   
See also in sourсe #XX -- [ Pg.235 ]




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1.2- Diols from alcohols

Alcohols amino alcohol

Alcohols diols

Amino alcohols

Amino diol

From 1,3-diols

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