Reduction of 4 tert butylcyclohexanone
However, such an answer is not correct, since the reaction is irreversible, resulting in the ratio of stereoisomeric products being determined by their relative rates of formation ; not by their relative thermodynamic stabilities.
What one does (both for exo and endo attack) is make a structure that one presumes is close to the structure of the transition state for attack of -BH4 on the carbonyl group.
As a result of this conformational immobility of the molecule, the sodium borohydride reduction of 4- t -butylcyclohexanone (in ethanol solvent at 25 degrees) from one side of the molecule gives trans -4- t -butylcyclohexanol as the major product, whereas reduction from the other side.The important product may be the trans product.When the optimization is finished the DHf for "exo reactant" will be displayed, and it may have a value like -94.1 kcal/mol.From the Edit menu select Save and save this structure as the "exo reactant." From the Applications menu select mopac, and optimize the geometry using AM 1 parameters (mopac does not contain PM 3 parameters for B, so PM 3 parameters cannot be used).Abstract: When 4-tert-butylcyclohexanone is normally microwaved in sodium borohydride and silica gel, a racemic mix is created.Ebbing, General Chemistry, Houghton Mifflin Company, Fifth Edition, 1996,.373.A value for DHf(exo) of -73.4 kcal/mol may be obtained.Save the structure as 4- t -butylcyclohexanone, and then cadeau noel 15 ans fille from the Applications menu select mopac and optimize the geometry of the 4- t -butylcyclohexanone molecule using the PM3 parameter set.To determine the melting stage, a Thomas Hoover Uni-Melt was used.Lock the distance between those two atoms at the value by selecting Lock from the Adjust menu.Cas Number: 98-53-3, einecs Number:, mDL Number: mfcd00001642.Trumper, Microscale Organic Laboratory, John Wiley Sons, Inc., Third Edition, 1994,.166.A value for DHf(endo) of -71.6 kcal/mol may be obtained.To determine the to determine the Infrared Spectroscopy, the FT-IR spectrophotometer Nicolet Ik100FT-IR was used.A cap was placed.The identity and percent of each stereoisomer present in the product mixture are established easily by proton-NMR1.LonD file and open.Figure 1, the question arises as to why the major stereoisomer formed is the trans isomer.Figure 5: The exo product Using the File menu, save the "exo product" structure.
Sodium borohydride (0.220g 4-tert-butylcyclohexanone (0.481g and silica gel (0.420g) had been all combined right into a mortar and grinded to create a good powder.
In the menu item entitled Calculation Type, select Find Transition State.