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For 1,2- and 1,4-disubstituted cyclohexane, a trans configuration, the diaxial conformation is effectively prevented by its high steric strain. For 1,3-disubstituted cyclohexanes, the cis form is diequatorial and the flipped conformation suffers additional steric interaction between the two axial groups.
trans-1,2-Diaminocyclohexane is an organic compound with the formula C 6 H 10 (NH 2) 2. This diamine is a building block for C 2-symmetric ligands that are useful in asymmetric catalysis. [1] A mixture of all three stereoisomers of 1,2-diaminocyclohexane is produced by the hydrogenation of o-phenylenediamine.
The repulsion between an axial t-butyl group and hydrogen atoms in the 1,3-diaxial position is so strong that the cyclohexane ring will revert to a twisted boat conformation. The strain in cyclic structures is usually characterized by deviations from ideal bond angles ( Baeyer strain ), ideal torsional angles ( Pitzer strain ) or transannular ...
In the absence of trans- alkyl groups, ring contraction may occur as the major product instead, i.e. the ring carbon itself may migrate. [3] [4] This reveals another interesting feature of the reaction, viz. that it is largely concerted. There appears to be a connection between the migration origin and migration terminus throughout the reaction.
1,2-Diaminocyclohexane (DACH) is an organic compound with the formula (CH 2) 4 (CHNH 2) 2. It is a mixture of three stereoisomers: cis-1,2-diaminocyclohexane and both enantiomers of trans-1,2-diaminocyclohexane. The mixture is a colorless, corrosive liquid, although older samples can appear yellow. It is often called DCH-99 and also DACH.
1,2-Dichloroethylene or 1,2-DCE is the name for a pair of organochlorine compounds with the molecular formula C 2 H 2 Cl 2. The two compounds are isomers, each being colorless liquids with a sweet odor. It can exist as either of two geometric isomers, cis-1,2-dichloroethene or trans-1,2-dichloroethene, but is often used as a mixture of the two ...
Most methylcyclohexane is extracted from petroleum but it can be also produced by catalytic hydrogenation of toluene: CH 3 C 6 H 5 + 3 H 2 → CH 3 C 6 H 11. The hydrocarbon is a minor component of automobile fuel, with its share in US gasoline varying between 0.3 and 1.7% in early 1990s [10] and 0.1 to 1% in 2011. [11]
Very often, cis–trans stereoisomers contain double bonds or ring structures. In both cases the rotation of bonds is restricted or prevented. [4] When the substituent groups are oriented in the same direction, the diastereomer is referred to as cis, whereas when the substituents are oriented in opposing directions, the diastereomer is referred to as trans.