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- Flippin–Lodge_angle abstract "The Flippin–Lodge angle (FL angle) is one of two angles used by organic and biological chemists studying the relationship between the structure of molecules and ways that they react, for a particular common type of chemical reaction. The angles—the Bürgi–Dunitz (BD) and the Flippin–Lodge (FL)—describe the "angle of attack" of an electron-rich reactant, the nucleophile, with an electron-poor reactant, an electrophile, in particular when the latter is planar in shape. This is called a nucleophilic addition reaction and it is plays a central role in the biological chemistry taking place in the biosyntheses of metabolism, and is a central reaction "tool" in the toolkit of modern organic chemistry for constructing new molecules such as pharmaceuticals. Theory and use of these angles falls into the specialty of physical organic chemistry, which deals with chemical structure and reaction mechanism, in particular, the area called structure correlation. Because reactions take place in three dimensions, their quantitative description is a geometry problem; two angles, first the BD, later the FL, were developed to describe the approach of the reactive atom of a nucleophile (a point off of a plane) to the reactive atom of an electrophile (a point on the plane). The BD is the angle between the line connecting these two atoms and a reference line that it intersects on the plane (see related article). The FL angle describes the extent to which the distinct plane containing both lines is offset from being perfectly perpendicular to the electrophile's plane (see figure). That is, it measures displacement of the nucleophile toward or away from the particular R and R' substituents attached to the electrophilic atom. FL and BD angle studies can be theoretical, based on calculations, or experimental (either quantitative, based on X-ray crystallography, or inferred and semiquantitative, rationalizing results of particular chemical reactions), or a combination of these. Addition reactions addressed using FL and BD angle concepts involve nucleophiles ranging from single atoms and polar organic functional groups to sophisticated enzyme active site and chiral catalyst-reactant systems. These nucleophiles can be paired with an array of planar electrophiles: aldehydes and ketones, carboxylic acid-derivatives, and the carbon-carbon double bonds of alkenes (olefins).The most prominent application and impact of the Flippin-Lodge angle has been in the area of chemistry where it was originally defined: in practical synthetic studies of the outcome of carbon-carbon bond-forming reactions in solution. An important example is the aldol reaction, e.g., addition of ketone-derived nucleophiles (enols, enolates), to aldehydes with attached groups varying in size and polarity. Of particular interest, given the three-dimensional nature of the concept, is understanding how features on the nucleophile and electrophile impact the stereochemistry of reaction outcomes (i.e., the "handedness" of new chiral centers created by a reaction). Studies invoking FL angles in synthetic chemistry have improved the ability of chemists to predict outcomes of known reactions, and to design better reactions to produce particular stereoisomers (enantiomers and diastereomers) needed in the construction of complex natural products and drugs.".
- Flippin–Lodge_angle thumbnail Flippin-Lodge-angle-2D.png?width=300.
- Flippin–Lodge_angle wikiPageID "19526078".
- Flippin–Lodge_angle wikiPageRevisionID "595705289".
- Flippin–Lodge_angle subject Category:Biochemistry.
- Flippin–Lodge_angle subject Category:Organic_chemistry.
- Flippin–Lodge_angle subject Category:Physical_organic_chemistry.
- Flippin–Lodge_angle comment "The Flippin–Lodge angle (FL angle) is one of two angles used by organic and biological chemists studying the relationship between the structure of molecules and ways that they react, for a particular common type of chemical reaction. The angles—the Bürgi–Dunitz (BD) and the Flippin–Lodge (FL)—describe the "angle of attack" of an electron-rich reactant, the nucleophile, with an electron-poor reactant, an electrophile, in particular when the latter is planar in shape.".
- Flippin–Lodge_angle label "Flippin–Lodge angle".
- Flippin–Lodge_angle sameAs Flippin%E2%80%93Lodge_angle.
- Flippin–Lodge_angle sameAs Q5459717.
- Flippin–Lodge_angle sameAs Q5459717.
- Flippin–Lodge_angle wasDerivedFrom Flippin–Lodge_angle?oldid=595705289.
- Flippin–Lodge_angle depiction Flippin-Lodge-angle-2D.png.