Stereoselective synthesis of 1,2-amino alcohols by asymmetric borane reduction of α-oxoketoxime ethers

Substituted 3‐Hydroxypyrroles from 1‐Azapenta‐1,4‐dien‐3‐ones:The Aza‐Nazarov Reaction – Synthesis and Quantum Chemical Calculations

“…2‐(Benzyloxyimino)‐5‐(4‐nitrophenyl)pent‐4‐en‐3‐one (10d): 3‐(Benzyloxyimino)butan‐2‐one ( 8a )41 (3.0 g, 15.7 mmol) and 4‐nitrobenzaldehyde (2.4 g, 15.9 mmol) were treated with a methanolic solution of potassium hydroxide (3.6 mL, 30 %, 19.2 mmol) at 0 °C. After addition of the base the aldehyde completely dissolved.…”

New 1,3-amino alcohols derived from enantiopure bridgehead β-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acids

“…They constitute convenient starting materials for the synthesis of various 1,3-heterocycles for example (Ager et al 1996;Fülöp et al 1997;Gyonfalvi et al 2003;Kivelä et al 2003Kivelä et al , 2005. Although 1,2-amino alcohols have received much attention because they are generally readily accessible in enantiomerically pure form from natural precursors (Gyonfalvi et al 2003;Reetz et al 1987;Delair et al 1994;Masui and Shiori 1998;Laczkowski et al 2009;, the synthesis and the use of chiral 1,3-amino alcohols are still undergoing development and remain a challenge (Lait et al 2007;Didier et al 1991; Barluenga et al 1993; Bartoli et al 1994;Kossenjans and Martens 1999;Kochi et al 2003;Raghavan et al 2004;Murai et al 2005;Balazs et al 2007). …”

3-Amino-2,6,6-trimethylbicyclo[3.1.1]heptan-2-ol

“…The in situ generated catalyst from ATBH and trimethyl borate has also been used in the stereoselective reduction of α-oxoketoxime ethers to prepare the corresponding chiral 1,2-amino alcohols. 4 Thus the asymmetric borane reduction of buta-2,3-dione monoxime ether followed by acidic work-up and subsequent reaction with benzyloxycarbonyl chloride affords a 90% yield of N-(Z)-3-aminobutan-2-ol with excellent enantioselectivities (eq 5). A trityl group in the oxime ether is required for high enantioselectivity.…”