Benzylamino alcohol

The reduction can be stopped at the benzylamino alcohol stage using an appropriate reducing agent. For example, in their general strategy to prepare pseudodistomins, Naito and co-workers reduced the bicyclic oxazohne 390 to the... 

Keywords benzylamino alcohol, microwave irradiation, retro-Diels-Alder reaction, unsaturated benzylamino alcohol... 

In addition to alcohols, some other nucleophiles such as amines and carbon nucleophiles can be used to trap the acylpalladium intermediates. The o-viny-lidene-/j-lactam 30 is prepared by the carbonylation of the 4-benzylamino-2-alkynyl methyl carbonate derivative 29[16]. The reaction proceeds using TMPP, a cyclic phosphite, as a ligand. When the amino group is protected as the p-toluenesulfonamide, the reaction proceeds in the presence of potassium carbonate, and the f>-alkynyl-/J-lactam 31 is obtained by the isomerization of the allenyl (vinylidene) group to the less strained alkyne. 

Friedel-Crafts reaction remains unexplored, possibly due to the difficulty of the cycloalkyne formation. A mild, versatile, and efficient method for the one-step synthesis of substituted dihydro- and tetrahydroisoquinolines has been developed by the FeCl3-6H20-catalyzed intramolecular allenylation/cyclization reaction of benzylamino-substituted propargylic alcohols, representing the first example of the intramolecular Friedel-Crafts reaction of propargylic alcohols (Scheme 8) [24, 25]. FeCls, InCls, and Yb(OTf)3 also exhibit good catalytic activity for the reaction. 

Finally (pathway e, Scheme 5.56), triazoline 103 formed by cyclo addition of azide to glycal 1 can be photolytically converted into a 1,2-aziridine intermediate 104, from which 2-benzylamino-2-deoxy-P-glucosides can be formed on addition of an alcohol and catalytic scandium triflate [176]. 

Sinou and coworkers evaluated a range of enantiopure amino alcohols derived from tartaric acid for the ATH reduction of prochiral ketones. Various (2R,iR)-i-amino- and (alkylamino)-l,4-bis(benzyloxy)butan-2-ol were obtained from readily available (-I-)-diethyl tartrate. These enantiopure amino alcohols have been used with Ru(p-cymene)Cl2 or Ir(l) precursors as ligands in the hydrogen transfer reduction of various aryl alkyl ketones ee-values of up to 80% have been obtained using the ruthenium complex [93]. Using (2R,3R)-3-amino-l,4-bis(benzyloxy)butan-2-ol and (2R,3R)-3-(benzylamino)-l,4-bis(benzyloxy)butan-2-ol with [lr(cod)Cl]2 as precursor, the ATH of acetophenone resulted in a maximum yield of 72%, 30% ee, 3h, 25 °C in PrOH/KOH with the former, and 88% yield, 28% ee, 120 h with the latter. 

The addition of different organometallics to the aldehyde function of 231, obtained by the regio- and diastereo-selective ring closure of (—)-8-(benzylamino)menthol 234 and 2-(t>-formylphenyl)acetaldehyde, resulted in formation of a mixture of diastereomeric secondary alcohols 232 and 233. The formation of the major diastereomers 232 was... 

Both enantiopure 1-substituted isochromenes and isochromans can be obtained from homophthalaldehyde through initial conversion to a perhydrobenzoxazine by reaction with (-)-8-(benzylamino)menthol. Acid-catalysed cyclisation of the separated diastereomeric alcohols arising from reaction with various organometallic compounds leads to isochromenes in toluene but to the isochroman in lower boiling alcohols (Scheme 15) <06EJO5110>. 

The general preparative route to 6-(benzyloxy)purine (4), an analog of the active synthetic cytokinin-6-(benzylamino)purine, involves the reaction of 6-chloropurine with sodium benzox-ide in benzyl alcohol. ... 

Directions for the preparation of 2-(benzylamino)pyridine in 99% yield from 2-pyridin-amine and benzyl alcohol are given in Organic Syntheses.1047... 

Notable new general syntheses of butenolides include the addition of the three-carbon synthon Li(PhS)C=CMeC02Me to aldehydes R CHO (R = alkyl or aryl) to yield the thioethers (19), the related reaction of lithio-j8-lithio-acrylates R CLi=CR C02Li with benzaldehyde to give compounds (20 R = H or Me), and the formation of (21) from the iodinated allyl alcohol ICMe=CHCH20H and carbon monoxide in the presence of bis(triphenylphos-phine)palladium(ii) chloride. Chloral reacts with dimethyl (benzylamino)fu-marate to yield the butenolide (22), whereas aromatic aldehydes give hydroxy-pyrrolinones (23). The total synthesis of piperolide (24) has been reported. 

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