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74 Chapter 4 CYCLOALKANES to C=C CH₃ δ Alkyne Ether (In norethynodrel and mestranol) (In mestranol) CH₃ CH₃ 46. α-Pinene is a monoterpene (10 carbons): CH₃ CH₃ Africanone is a sesquiterpene: CH₃ CH₃ 0 CH₃ 47. If pure p orbitals were used for the C-C bonds of cyclobutane, then each carbon could be sp hybridized: H sp orbitals used for C-H bonds orbitals C H The H-C-H bond angle would be 180° and cyclobutane would look like this: H H H H H H H H In reality, cyclobutane uses "bent" bonds just like those of cyclopropane, and all four bonds to each carbon involve hybridized orbitals. In addition, cyclobutane is not flat at all, and the H-C-H bond angle is not much different from the normal tetrahedral value of 109° (see Figure 4-3). 48. Notice that making "all-chair" cyclodecane is essentially the same as removing the ring-fusion bond from trans-decalin and replacing it with two hydrogens-one on each former ring-fusion carbon: H H H H Add H Remove two H. bond H H H