1 -Amino-3,4-diols

The prodiicls are reduced lo amino diols with Hj-Raney Ni in ethanol withoiil loss of configiiradoiial purity fEq. 3.67i. 

Cleavage of the acetals 9 provides crystalline amino diol hydrochlorides. Remarkably, the (S.S.S)-diastereomer crystallized preferentially leading to a considerable enhancement of d.r. values. 

To the solution of (4S,5S, 5 S,)-5-(2-alkenylarnino)- or (4S,5S ,5 S )-5-(2-alkynylamino)-2,2,-dimethyl-4-phenyl-1.3-dioxane 9 obtained above in 30 raL of Et20 are added dropwise 30 mL of3N HC1 at 0 CC. Then the mixture is allowed to warm to r.t. over 12 h. The resulting precipitate is rccrystallizcd from CH2C12/Et20 (1 1) and treated with 2.5 N NaOH to provide the amino diol 10 which is extracted with 300 mL of Et,0 yield 81 87%. 

The products are reduced to amino diols with H2-Raney Ni in ethanol without loss of configurational purity (Eq. 3.67).109... 

M. L. Testa, R. Ciriminna, C. Hajji, E. Zaballos Garcia, M. Ciclosi, J. Sepulveda Arques and M. Pagliaro, Oxidation of Amino Diols Mediated by Homogeneous and Heterogeneous TEMPO, Adv. Synth. Catal., 2004, 346, 655. 

The ammonium salt la is debenzylated to a single amino diol in quantitative yield from 3a, which is then desilylated with Dowex 50W-X8 (H form) and washing the resin with 10% NH4OH followed by lyophilisation of the eluates gives (-) swainsonine i in 84% yield, identical by direct comparison with an authentic sample. 

An interesting innovation involves the use of isopropenyl acetate or acetic anhydride to accomplish irreversible acyl transfer63, as exemplified in the resolution of 1-phenylethanol (12) and the amino diol derivative 3- cr/ butyl-5-(2-hydroxyethyl)-2-oxazolidinone (14) ( ) ... 

The isolation of the diaquo-nitrate depends on its sparing solubility, on account of which it may be precipitated from a solution in which there is equilibrium between the ju-amino-ol and the /x-amino-diol compounds, by means of nitric acid thus ... 

From the same solution, therefore, ammonium nitrate is capable of forming the diaquo-p,-amino-ol salt, whereas ammonium bromide and ammonium iodide yield respectively the bromide and the iodide of the p,-amino-diol salt.2... 

To reach chiral cyclohexanones, we have found that the bicyclic lactam 10, derived from 5-oxohexanoic acid and the commercially available amino diol, gave excellent results. A number of examples were obtained (Table I).8... 

Evans reported an enantioselective Meerwein-Ponndorf-Verley reduction using a catalytic amount of chiral samarium complex 26 prepared from samarium (III) iodide and a chiral amino diol (Scheme 9.16) [34], Even when a partially resolved ligand (80% ee) was used, the enantiopurity of the resulting alcohol 27 reached 95% ee, which is the same value as that obtained when the enantiopure amino diol was used. 

The amino diol was purchased from Aldrich Chemical Company, Inc. and was recrystallized before use from methanol/ethyl acetate (the material used had mp 111-113°C). 

The possibility to obtain amino diols from (3-amino-ot-hydroxy esters (see above) was crucial in the exploration of an AA approach towards D-ango-... 

The remaining unreacted (RJ-20 can be trapped with an aldehyde such as pivalaldehyde giving the chiral homopro-pargylic alcohol in 87.5% ee.74 This kinetic resolution has been used to prepare anti/inti-vicinal amino diols in > 95% ee and dr > 40 l.75 In general, diorganozincs are more easily prepared in optically pure form. On another hand, secondary zinc reagents prepared by the direct zinc insertion to secondary alkyl iodides are obtained without stereoselectivity (Scheme 4).76... 

Different polar functional groups bonded onto silica can also be used for normal phase. The most frequently used bonded phases are amino-, diol-, cyano-, and nitro-groups. These phases, when used in the normal mode, are similar to adsorption onto silica gel. The use of bonded-phase columns in the normal phase mode is shown in Figure 5-44. There is a different order of elution on the amino-bonded phase compared to the cyano phase and different elution than on silica (ortho < meta < para), which is not shown. This is due to interactions with the functional groups on the packing rather than solely with the hydroxyl groups on the silica gel. 

Amino-l,3-dioxepines were synthesised as potential new non-steroidal antiinflammatory agents by the reaction of an aldehyde with the appropriate amino-diols <07BMC6273> while benzodioxepines related to the marine odorant Calon 1951 have been synthesised and the nature of substituents on olfactory character analysed <07HCA854, 07HCA1006>. 

The thermal rearrangement of O-allyl trichloroacetimidates 1 affords the corresponding 7V-allyl amides 31 2, which have been cyclized with the aim of obtaining amino diols or amino alcohols different to those from the cyclization of the trichloroacetimidates. Cyclization of these latter substrates 1 leads to 4,5-dihydro-4-(l-iodoalkyl)oxazoles 2, while treatment of unsaturated trichloroacetamides 3 with /V-iodosuccinimide3 in chloroform affords the corresponding 4,5-dihydro-5-(l-iodoalkyl)oxazoles 4 in high yield. These heterocyclic products are protected forms of the corresponding amino alcohols. 

Reaction of amino diols with a fatty acid afforded a series of simple ceramide analogs with pro-apoptotic activity in human cancer cell lines (160). An example is Ai-oleoylserinol, which induced apoptosis in cells expressing the pro-apoptotic protein PAR-4 and was used to purge transformed cells from embryonic stem cells before implantation into mouse brain (161). 

A LAH complex (54) prepared from 2.28 equiv. of the amino diol (19) reduces acetophenone and pro-piophenone to the corresponding (f )-alcohols with 82% ee and 77% ee, respectively. The key feature of this carbinolamine-modified LAH reagent is a lithium ion chelate. 

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