NOBIN (2-amino-2'-hydroxy-1,1'-binaphthyl) is an organic molecule used for

asymmetric catalysis Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of Chirality (chemistry), chirality are formed ...

. NOBIN is related to BINOL and other analogs by both having a chiral axis and being a scaffold for certain chemical reactions. NOBIN is an excellent catalyst for the

aldol reaction The aldol reaction (aldol addition) is a Chemical reaction, reaction in organic chemistry that combines two Carbonyl group, carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might invol ...

producing reliable products, good yields, and excellent

diastereoselectivity In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have d ...

. Though rotation around the bond joining the rings is limited by the hydrogen atoms, enantiomerically pure NOBIN may

racemize In chemistry, racemization is a conversion, by heat or by chemical reaction, of an optically active compound into a racemic (optically inactive) form. This creates a 1:1 molar ratio of enantiomers and is referred to as a racemic mixture (i.e. conta ...

upon heating. NOBIN is prepared by oxidative cross coupling of

2-naphthol 2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are ...

and

2-naphthylamine 2-Naphthylamine or 2-aminonaphthalene is one of two isomeric aminonaphthalenes, compounds with the formula C10H7NH2. It is a colorless solid, but samples take on a reddish color in air because of oxidation. It was formerly used to make azo dyes, b ...

. The oxidative source is metal ions in solution such as Fe²⁺ or a Cu²⁺ amine complex. Once

racemic In chemistry, a racemic mixture or racemate () is a mixture that has equal amounts (50:50) of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as r ...

NOBIN is produced, it needs to be resolved. One method for this is the use of

camphorsulfonic acid Camphorsulfonic acid, sometimes abbreviated CSA or 10-CSA is an organosulfur compound. Like typical sulfonic acids, it is a relatively strong acid that is a colorless solid at room temperature and is soluble in water and a wide variety of organic ...

, in which the basic group of NOBIN is used to form a diastereomeric salt of one

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

. The other enantiomer however will stay in solution. :{{clear-left

References

*Kocovsky, Smrcina, Lorenc, Hanus; ''Synlett'';(1991) 231 *Ding, Li; Ten years of research on NOBIN chemistry: ''Current Organic Synthesis'';(2005);2;499-545 Catalysts 2-Naphthols Naphthylamines