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In stereochemistry, a stereocenter of a molecule is an atom (center), axis or plane that is the focus of stereoisomerism; that is, when having at least three different groups bound to the stereocenter, interchanging any two different groups creates a new stereoisomer. [1] [2] Stereocenters are also referred to as stereogenic centers.
A stereogenic center (or stereocenter) is an atom such that swapping the positions of two ligands (connected groups) on that atom results in a molecule that is stereoisomeric to the original. For example, a common case is a tetrahedral carbon bonded to four distinct groups a , b , c , and d (C abcd ), where swapping any two groups (e.g., C bacd ...
A meso compound is an achiral molecule, despite having two or more stereogenic centers. A meso compound is superposable on its mirror image, therefore it reduces the number of stereoisomers predicted by the 2 n rule.
In this approach: identify the chiral center, label the four atoms directly attached to the stereogenic center in question, assign priorities according to the sequence rule ( from 1 to 4), rotate the molecule until the lowest priority (number 4) substituent is away from the observer/viewer, draw a curve from number 1 to number 2 to number 3 ...
Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. [1] The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space.
Left handed molecules have l- prefixed to their names; d- is prefixed to right handed molecules. However, this d-and l-notation of distinguishing enantiomers does not say anything about the actual spatial arrangement of the ligands/substituents around the stereogenic center, which is defined as configuration
Stereocenter (stereogenic center, stereogenic atom): An atom at which the interchange of substituents (ligands) gives rise to stereoisomers. Examples are 2-bromobutane with one stereocenter and 2-butene with two stereocenters. There are also 5-coordinate and 6-coordinate stereocenters using other atoms.
Chiral auxiliaries are incorporated into synthetic routes to control the absolute configuration of stereogenic centers. David A. Evans' synthesis of the macrolide cytovaricin, considered a classic, utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting the absolute stereochemistry of nine stereocenters.