The structure of (-)-$\alpha$-pinene is shown in the figure.

<MultiModal>![[C@H]12C[C@H](CC=C1C)C2(C)C](/media/uploads/0a26cdce-f0a9-4789-a271-edb910bb7075.png)</MultiModal>

The specific rotation of a solution of (-)-$\alpha$-pinene is $-50.7\degree$. (-)-$\alpha$-Pinene is mixed with its enantiomer in a certain ratio, and the specific rotation of the resulting solution is $-12\degree$. Calculate the enantiomeric excess e.e. of the mixture.

(-)-$\alpha$-Pinene is added to $5 \% \mathrm{H}_{2} \mathrm{SO}_{4}$ to generate an optically inactive product $\mathbf{A}$.

At low temperature, (-)-$\alpha$-pinene reacts with one equivalent of $\rm HCl$ in diethyl ether to produce $\bf B_1$ and $\mathbf { B_2 }$. If the reaction is carried out at room temperature, the products are $\bf B_3$ and a small amount of $\bf B_4$. The formation of $\bf B_1, B_2, B_3, B_4$ all proceed through a single intermediate. $\bf B_1$ and $\bf B_2$ are stereoisomers, and $\bf B_3$ and $\bf B_4$ are constitutional isomers. The rate of elimination reaction with sodium ethoxide: $\bf B _ { 2 } > \bf B_ { 1 }$.

(-)-$\alpha$-Pinene reacts with $\mathrm{NOCl}$, and then treated with $\mathrm{KOH}$ to generate compound $\mathbf{C}$. $\bf C$ is treated with $\mathrm{Zn} / \mathrm{CH}_{3} \mathrm{COOH}$ to obtain stereoisomers $\mathbf{D_1}$ and $\mathbf{D_2}$. The rate of reaction with 2-chloropentane: $\mathbf{D_1}>\mathbf{D_2}$.

Which of the following options is correct:
(-)-$\alpha$-蒎烯的结构如图

<MultiModal>![[C@H]12C[C@H](CC=C1C)C2(C)C](/media/uploads/0a26cdce-f0a9-4789-a271-edb910bb7075.png)</MultiModal>

(-)-$\alpha$-蒎烯的溶液的比旋光度为$-50.7\degree$ 。将 (-)-$\alpha$-蒎烯与其对映体按一定比例混合, 所得溶液的比旋光度为 $-12\degree$ 。求该混合物的对映体过量 e.e. 

将(-)- $\alpha$-蒎烯加入 $5 \% \mathrm{H}_{2} \mathrm{SO}_{4}$ 中,生成无旋光性的产物 $\mathbf{A}$ 。

在低温下， (-)-$\alpha$-蒎烯与一当量的$\rm HCl$在乙醚中反应，产物为$\bf B_1$和 $\mathbf { B_2 }$ 。若反应在室温下进行，则产物为$\bf B_3$以及少量的$\bf B_4$。$\bf B_1, B_2, B_3, B_4$的生成均只经过唯一的中间体。$\bf B_1$和 $\bf B_2$ 为立体异构， $\bf B_3$ 和 $\bf B_4$ 为构造异构。与乙醇钠发生消除反应的速率： $\bf B _ { 2 } > \bf B_ { 1 }$ 。

(-)-$\alpha$-蒎烯与 $\mathrm{NOCl}$ 反应, 再用 $\mathrm{KOH}$ 处理, 生成化合物 $\mathbf{C}$ 。$\bf C$ 用 $\mathrm{Zn} / \mathrm{CH}_{3} \mathrm{COOH}$ 处理得到立体异构体 $\mathbf{D_1}$ 和 $\mathbf{D_2}$ 。与 2 -氯戊烷反应的速率:$\mathbf{D_1}>\mathbf{D_2}$ 。

下列选项正确的是：
All options other than A and B are incorrect.
Other than A and B, more than 1 option is correct.
The e.e. value of the mixture is greater than $25\%$
The molecular weight of $\bf A$ is less than 170.
The structure of $\bf B_1$ is <MultiModal>![C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](/media/uploads/29b77b69-51ae-4187-b3e3-fd1ffa7510a0.png)</MultiModal>
$\bf B_4$'s structure is <MultiModal>![C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2](/media/uploads/0001644c-7034-4ce4-8677-d9261325e636.png)</MultiModal>
The structure of $D_1$ is <MultiModal>![C1[C@H](N)C(=C)[C@@H]2C[C@H]1C2(C)C](/media/uploads/e28d9cda-1211-4846-b60a-ce95d67f2bad.png)</MultiModal>
除A, B外其他选项均不正确
除A, B外, 有多于1个选项正确
混合物的e.e.值大于$25\%$
$\bf A$的分子量小于170
$\bf B_1$的结构为<MultiModal>![C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](/media/uploads/29b77b69-51ae-4187-b3e3-fd1ffa7510a0.png)</MultiModal>
$\bf B_4$的结构为<MultiModal>![C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2](/media/uploads/0001644c-7034-4ce4-8677-d9261325e636.png)</MultiModal>
$\bf D_1$的结构为<MultiModal>![C1[C@H](N)C(=C)[C@@H]2C[C@H]1C2(C)C](/media/uploads/e28d9cda-1211-4846-b60a-ce95d67f2bad.png)</MultiModal>
Mixture's enantiomeric excess e.e. $= |[α]_{mix}|/|[α]_{pure}|×100\% = 12/50.7 = 23.7\%$.

It can be seen that e.e. is no greater than 25%. Therefore, option C is incorrect.

<Checkpoint>[e.e. $= 23.7\%$, option C is incorrect](0.5)</Checkpoint>

Under $\rm 5\% H_2SO_4$ conditions, α-pinene is protonated to obtain a carbocation, undergoing ring-opening and addition to obtain $\bf A$ as shown in the figure below:

<MultiModal>![CC(O)([C@H]1CC[C@@H](O)CC1)C](/media/uploads/ec239eec-1427-4782-82c3-e41058042f90.png)</MultiModal>

The molecular formula is $\rm C_{10}H_{20}O_2$, and the molecular weight is 172.26, option D is incorrect.

<Checkpoint>[$\bf A$'s molecular formula is $\rm C_{10}H_{20}O_2$, molecular weight is 172.26, greater than 170, option D is incorrect](1)</Checkpoint>

<Checkpoint>[$\bf A$'s structure is CC(O)([C@H]1CC[C@@H](O)CC1)](1)</Checkpoint>

The classical pinene-hydrochloric acid reaction proceeds through a unique non-classical carbocation intermediate. At low temperatures, the chloride anion is rapidly intercepted, yielding a pair of stereoisomeric chlorides $\bf B_1, B_2$. At higher temperatures, it is further converted to structurally isomeric $\bf B_3, B_4$ via Wagner–Meerwein rearrangement (commonly described as bornyl chloride $\bf B_3$ and a small amount of fenchyl chloride $\bf B_4$ in biology), which are structural isomers of each other.

The elimination rates (sodium ethoxide) of $\bf B_1$ and $\bf B_2$ are different, $\bf B_2 > B_1$, reflecting the difference in the accessibility of their trans-elimination (trans-coplanar geometry), which is consistent with the two stereoisomers (same skeleton) obtained at low temperatures.

<Checkpoint>[$\bf B_1$ undergoes E2 elimination reaction slower than $\bf B_2$, indicating that $\bf B_1$ is a trans structure, option E is incorrect](1)</Checkpoint>

The $\bf B_4$ structure given in option F does not match the corresponding relationship between the skeleton and the substitution position of the classical minor product (anisole/anisyl chloride), which is incorrect.

<MultiModal>![$\bf B_1$: C1C[C@@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]; $\bf B_2$: C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]; $\bf B_3$: C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2; $\bf B_4$: C1C[C@@]2(C[C@H]1C(C)(C)[C@@H]2Cl)C](/media/uploads/799bcee0-ba4a-4361-b53a-2d0d7be8d2be.png)</MultiModal>

<Checkpoint>[During this rearrangement reaction, the migration rate of the quaternary carbon is faster, and the option's structure is the major product $\bf B_3$, option F is incorrect](1)</Checkpoint>

<Checkpoint>[$\bf B_1$'s structure is C1C[C@@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](1)</Checkpoint>

<Checkpoint>[$\bf B_2$'s structure is C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](1)</Checkpoint>

<Checkpoint>[$\bf B_3$'s structure is C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2](1)</Checkpoint>

<Checkpoint>[$\bf B_4$'s structure is C1C[C@@]2(C[C@H]1C(C)(C)[C@@H]2Cl)C](1)</Checkpoint>

The addition of $\alpha$-pinene and $\rm NOCl$ yields a chlorinated hydrocarbon containing a nitroso group. Under alkaline conditions, the nitroso group tautomerizes to an oxime, and then an elimination reaction occurs to obtain $\bf C$;

<MultiModal>![$\bf C$结构为C1C(=NO)C(=C)[C@]2([H])C[C@@]1([H])C2(C)C](/media/uploads/d2205338-93e4-4383-84a0-33cd4b3388af.png)</MultiModal>

<Checkpoint>[$\bf C$'s structure is C1C(=NO)C(=C)[C@]2([H])C[C@@]1([H])C2(C)C](1)</Checkpoint>

$\rm Zn/AcOH$ reduction yields the corresponding amine. The generated amine has two stereoisomers (exo/endo), where the exo-substituted amine has less steric hindrance and exhibits a more pronounced nucleophilicity, resulting in a faster substitution reaction (quaternization) with secondary haloalkanes (such as 2-chloropentane), so $\bf D_1 > D_2$.

<MultiModal>![$\bf D_1$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@@H]1N)[H], $\bf D_2$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@H]1N)[H]](/media/uploads/7a13d1b4-291c-4c5b-b808-70953ff809d6.png)</MultiModal>

The $\bf D_1$ structure given in option G is the endo-camphornene amine configuration, which does not match the rate comparison. Therefore, G is incorrect.

<Checkpoint>[The exo-substituted amine has less steric hindrance and exhibits a more pronounced nucleophilicity, resulting in a faster substitution reaction with secondary haloalkanes](1)</Checkpoint>

<Checkpoint>[$\bf D_1$'s structure is C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@@H]1N)[H]](1)</Checkpoint>

<Checkpoint>[$\bf D_2$'s structure is C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@H]1N)[H]](1)</Checkpoint>

In summary: C, D, E, F, and G are all incorrect, so A should be selected.
混合物的对映体过量 e.e. $= |[α]_{mix}|/|[α]_{pure}|×100\% = 12/50.7 = 23.7\%$。

由此可见 e.e. 并不大于 25%。故选项C错误。

<Checkpoint>[e.e. $= 23.7\%$, 选项C错误](0.5)</Checkpoint>

$\rm 5\% H_2SO_4$ 条件下，α-蒎烯质子化得到碳正离子, 发生开环与加成，得到如下图所示的$\bf A$：

<MultiModal>![CC(O)([C@H]1CC[C@@H](O)CC1)C](/media/uploads/ec239eec-1427-4782-82c3-e41058042f90.png)</MultiModal>

分子式为$\rm C_{10}H_{20}O_2$, 分子量为172.26，选项D错误

<Checkpoint>[$\bf A$分子式为$\rm C_{10}H_{20}O_2$, 分子量为172.26, 大于170, 选项D错误](1)</Checkpoint>

<Checkpoint>[$\bf A$结构为CC(O)([C@H]1CC[C@@H](O)CC1)](1)</Checkpoint>

经典的蒎烯-盐酸反应经唯一的非经典碳正离子中间体，低温时氯阴离子迅速截获，得到一对立体异构的氯化物$\bf B_1, B_2$；在较高温度经Wagner–Meerwein重排进一步转化为构造异构的$\bf B_3, B_4$ （常见表述为生物里冰片基（bornyl）氯化物 $\bf B_3$ 及少量的葑烷基（fenchyl）氯化物 $\bf B_4$），二者互为构造异构体。

$\bf B_1$ 与 $\bf B_2$ 的消除（乙醇钠）速率不同，$\bf B_2 > B_1$，反映了它们在反式消除（反式共面几何）可达性上的差异，这与低温所得的两立体异构体（同一骨架）相符。

<Checkpoint>[$\bf B_1$ 相较 $\bf B_2$发生E2消除反应的速率更慢，说明$\bf B_1$为反式结构, 选项E错误](1)</Checkpoint>

选项F给出的 $\bf B_4$ 结构与经典的少量产物（茴香烷/茴香基氯化物）在骨架与取代位置的对应关系不符，错误。

<MultiModal>![$\bf B_1$: C1C[C@@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]; $\bf B_2$: C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]; $\bf B_3$: C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2; $\bf B_4$: C1C[C@@]2(C[C@H]1C(C)(C)[C@@H]2Cl)C](/media/uploads/799bcee0-ba4a-4361-b53a-2d0d7be8d2be.png)</MultiModal>

<Checkpoint>[在此重排反应过程中, 季碳的迁移速率更快, 选项中的是主要产物$\bf B_3$, 选项F错误](1)</Checkpoint>

<Checkpoint>[$\bf B_1$结构为C1C[C@@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](1)</Checkpoint>

<Checkpoint>[$\bf B_2$结构为C1C[C@](Cl)(C)[C@@]2(C[C@@]1([H])C2(C)C)[H]](1)</Checkpoint>

<Checkpoint>[$\bf B_3$结构为C1[C@@H](Cl)[C@]2(C)C(C)(C)[C@H]1CC2](1)</Checkpoint>

<Checkpoint>[$\bf B_4$结构为C1C[C@@]2(C[C@H]1C(C)(C)[C@@H]2Cl)C](1)</Checkpoint>

$\alpha$-蒎烯与$\rm NOCl$加成得到含有亚硝基的氯代烃，碱性条件下亚硝基互变异构为肟, 再发生消除反应得到$\bf C$；

<MultiModal>![$\bf C$结构为C1C(=NO)C(=C)[C@]2([H])C[C@@]1([H])C2(C)C](/media/uploads/d2205338-93e4-4383-84a0-33cd4b3388af.png)</MultiModal>

<Checkpoint>[$\bf C$结构为C1C(=NO)C(=C)[C@]2([H])C[C@@]1([H])C2(C)C](1)</Checkpoint>

$\rm Zn/AcOH$ 还原得到相应胺。生成的胺有两种立体异构（exo/endo），其中外向（exo）取代的胺位阻更小、亲核性显现更充分，对二级卤代烷（如2-氯戊烷）的取代反应（季铵化）更快，故 $\bf D_1 > D_2$。

<MultiModal>![$\bf D_1$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@@H]1N)[H], $\bf D_2$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@H]1N)[H]](/media/uploads/7a13d1b4-291c-4c5b-b808-70953ff809d6.png)</MultiModal>

选项G给出的$\bf D_1$结构是内向（endo）的樟脑烯胺构型，不符合速率比较。故G错误。

<Checkpoint>[外向（exo）取代的胺位阻更小、亲核性显现更充分，对二级卤代烷的取代反应更快](1)</Checkpoint>

<Checkpoint>[$\bf D_1$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@@H]1N)[H]](1)</Checkpoint>

<Checkpoint>[$\bf D_2$结构为C1[C@@]2(C(C)(C)[C@](C2)([H])C(=C)[C@H]1N)[H]](1)</Checkpoint>

综上：C、D、E、F、G均不成立，应选A。