Indanol

Both enantiomers of (Z)-l-amino-2-indanol are available commercially. 

Table 11.8 Reduction of ketones using 7V-(2-pyridinesulfonyl)-l-amino-2-indanol as a ligand.

Ricci and co-workers introduced a new class of amino- alcohol- based thiourea derivatives, which were easily accessible in a one-step coupling reaction in nearly quanitative yield from the commercially available chiral amino alcohols and 3,5-bis(trifluoromethyl)phenyl isothiocyanate or isocyanate, respectively (Figure 6.45) [307]. The screening of (thio)urea derivatives 137-140 in the enantioselective Friedel-Crafts reaction of indole with trans-P-nitrostyrene at 20 °C in toluene demonstrated (lR,2S)-cis-l-amino-2-indanol-derived thiourea 139 to be the most active catalyst regarding conversion (95% conv./60h) as well as stereoinduction (35% ee), while the canditates 137, 138, and the urea derivative 140 displayed a lower accelerating effect and poorer asymmetric induction (Figure 6.45). The uncatalyzed reference reaction performed under otherwise identical conditions showed 17% conversion in 65 h reaction time. 

Enantiomerically pure epoxides and diols, readily available through the asymmetric epoxidation and asymmetric dihydroxylation reactions, are ideal precursors to prepare cis-amino alcohols via the Ritter reaction. " " A Merck group has shown that indene oxide 175a can be converted effectively to c/i-l-amino-2-indanol, a key fragment of the HlV-protease inhibitor Indinavir via the cis-... 

Chloroform was evaporated to give 13 g desired 2-(l-aminopropyl)-2-indanol. MP 92°C. Yield 33%. IR spectrum and thin layer chromatography confirmed the structure of prepared compound. 

Racemic substituted aminoindanol 9 was synthesized in a 5-step sequence by nitration of 1-indanone, followed by ketone reduction and dehydration to give 6-nitro-l-indene and subsequent epoxidation of the olefin and final regioselective animation (Scheme 8.5). Optically pure (IR,2R)-and (1 S,2S)-6-nitro-1 -amino-2-indanol 9 were eventually obtained by resolution with mandelic... 

Since the discovery of cis-1 -amino-2-indanol as a ligand for human immunodeficiency virus protease inhibitors and the development of a practical industrial process for the synthesis of either ris-isomers in enantiopure form, the remarkable properties of the rigid indane platform have been used extensively in an ever-increasing number of asymmetric methodologies. In addition to the use of this amino alcohol as a chiral auxiliary and ligand for asymmetric synthesis, it has found application as a useful resolution agent. Applications include amines, carboxylic acids, and alcohols. 

In particular, reduction of unsymmetric ketones to alcohols has become one of the more useful reactions. To achieve the selective preparation of one enantiomer of the alcohol, chemists first modified the classical reagents with optically active ligands this led to modified hydrides. The second method consisted of reaction of the ketone with a classical reducing agent in the presence of a chiral catalyst. The aim of this chapter is to highlight one of the best practical methods that could be used on an industrial scale the oxazaborolidine catalyzed reduction.1 1 This chapter gives an introductory overview of oxazaborolidine reductions and covers those of proline derivatives in-depth. For the oxazaborolidine derivatives of l-amino-2-indanol for ketone reductions see Chapter 17. 

Enantiomerically pure d.v-1 -amino-2-indanol and its derivatives have been used as ligands in numerous catalytic asymmetric carbon-hydrogen, carbon-carbon, and carbon-heteroatom bond formation reactions. The conformationally constrained indanyl platform has emerged as a particularly valuable backbone in a variety of catalytic processes leading to high levels of asymmetric induction. The aminoindanol 1 has also been used as a resolution agent (Chapter 8) as well as a chiral auxiliary (Chapter 24). For the synthesis of 1 see Chapter 24. 

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