Sachse Mohr Theory l Study Pharma l

Sachse Mohr theory:
According to Hermann Sachse, the theory states that cycloalkanes higher members such as six or above are free from angle strain because all the carbon atoms of higher member cycloalkanes do not forced  each other into one plane, So that all the carbon atoms of higher member cycloalkanes are in different planes. Hence higher member cycloalkanes exhibits the bond angle 109.5 degree (without any strain). Its mean higher member cycloalkanes are 'puckered' in conformation.
Example:

Note:
Hermann Sachse also follow the 109.5 degree optimum angle.
Cyclohexane has two conformation one is Chair form and another is Boat form
Chair form is more stable than Boat form because in Chair form all carbons atoms staggered whereas in Boat form C2 -C3 and C5-c6 are eclipsed. that why chair form is more stable than Boat form.

Stability and Reactivity:
According to Sachse, Order of Stability:

Cyclohexane > Cyclopentane > Cyclobutane > Cyclopropane

According to Sachse, Order of Reactivity:

Cyclopropane > Cycobutane > Cyclopentane > Cyclohexane

Hermann Sachse Vs Adolf Von Baeyer
1. Hermann Sachse tells no effect of angle strain on higher member cycloalkanes(beacause higher member cycloalkanes are in different planes,  exhibits the bond angle 109.5 degree without any strain) whereas Adolf Von Baeyer not explain it.
2. Hermann Sachse proved that higher member cycloalkanes are exists and they don't have angle strain (+ve or -ve) whereas Adolf Von Baeyer not explain why negative angle strain compounds not exists.
3. According to Hermann Sachse,  Order of Stability:

Cyclohexane > Cyclopentane > Cyclobutane > Cyclopropane

whereas 
According to Baeyer,  Order of Stability:

Cyclopentane > Cyclohexane > Cyclobutane > Cyclopropane

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