Formula sheet

Notation: C* (asymmetric carbon marked with an asterisk) · n · a · m · r = a/2 · d / (+) dextrorotatory, l / (−) laevorotatory, dl / (±) racemic · D / L (with respect to glyceraldehyde) · cis / trans for alkenes and rings, syn / anti for C=N and N=N, E / Z mentioned only · [α] at t °C and wavelength λ · α_obs · l (in dm) · C (g/mL) · % ee (optical purity, O.P.) · D.B.E. (degree of unsaturation) · θ · x_a (anti), x_g (gauche) · μ (Debye) · a (axial), e (equatorial). D.B.E. valency terms: C +2, N +1, O/S 0, H/halogen −1. Sodium D-line λ = 5893 Å.

Learning path · Formula sheet · Practice set

Print and revise: Revision sheet (PDF) · Formula sheet (PDF, one page)

Part 4 · Tautomerism and Keto-Enol Equilibrium

Enol order: CH₃COCH₃ < CH₃COCH₂COOC₂H₅ < C₆H₅COCH₂COOC₂H₅ < CH₃COCH₂CHO < CH₃COCH₂COCH₃ < C₆H₅COCH₂COCH₃ < cyclohexane-1,3-dione < C₆H₅COCH₂COC₆H₅ Factors that stabilise the enol

Part 6 · Degree of Unsaturation and Counting Isomers

D.B.E. = \frac{\sum n ( v - 2 )}{2} + 1

Double bond equivalent

Part 7 · Geometrical (cis-trans) Isomerism

N = 2^{n} (unsymmetrical)

Number of geometrical isomers in polyenes

N = 2^{n - 1} + 2^{n /2 - 1} (symmetrical, n even)

Number of geometrical isomers in polyenes

N = 2^{n - 1} + 2^{(n - 1) /2} (symmetrical, n odd)

Number of geometrical isomers in polyenes

Part 8 · Optical Activity, Symmetry and Chirality

[α] = \frac{α _{obs}}{l \times C}

Specific rotation

Part 10 · Lactic Acid, Tartaric Acid and Counting Stereoisomers

a = 2^{n}, m = 0

Number of optical isomers

a = 2^{n - 1}, m = 2^{n /2 - 1}

Number of optical isomers

a = 2^{n - 1} - 2^{(n - 1) /2}, m = 2^{(n - 1) /2}

Number of optical isomers

total = a + m

Number of optical isomers

r = \frac{a}{2}

Number of optical isomers

Part 11 · Racemic Mixtures, Optical Purity and Configuration

% ee = \frac{n _{1} - n _{2}}{n _{1} + n _{2}} \times 100

Enantiomeric excess and optical purity

% ee = \frac{[ α ] _{obs}}{[ α ] _{pure}} \times 100

Enantiomeric excess and optical purity

[α]_{obs} = \frac{% ee}{100} \times [α]_{pure}

Enantiomeric excess and optical purity

Part 13 · Conformations of Ethane, Propane and Butane

Stability: anti > gauche > partially eclipsed > fully eclipsed n-Butane

μ = μ_{anti} x_{a} + μ_{gauche} x_{g}

Mole fraction of anti and gauche conformers

x_{a} + x_{g} = 1

Mole fraction of anti and gauche conformers

Part 14 · Conformations of Cyclohexane

d = \frac{1}{2} (10 9^{\circ} 2 8^{'} - ring angle)

Baeyer strain theory

cyclopropane 24°44′, cyclobutane 9°44′, cyclopentane 0°44′, cyclohexane −5°16′ Baeyer strain theory

Stability: chair > twist boat > boat > half chair Chair and boat cyclohexane

1,2: trans = ee/aa, cis = ae Disubstituted cyclohexanes

1,3: cis = ee/aa, trans = ae Disubstituted cyclohexanes

1,4: trans = ee/aa, cis = ae Disubstituted cyclohexanes