Diphenylcyclopropenone can undergo the following reaction:

<MultiModal>![`COC1=CC(OS(=O)(C(F)(F)F)=O)=C([Si](C)(C)C)C=C1OC` and `O=C1C(C2=CC=CC=C2)=C1C3=CC=CC=C3` react with cesium fluoride in acetonitrile to generate $\bf{A}$, and $\bf{A}$ generates `COC1=C(OC)C=C(C(/C(C2=CC=CC=C2)=C\C3=CC=CC=C3)=C(C=C(OC)C(OC)=C4)C4=[O+]5)C5=C1` under the action of $TfOH$](/media/uploads/c0ce34a9-b607-4fb9-932e-bde700f4ce33.png)</MultiModal>

Examine the structural formula of $\bf{A}$ and the structures of the three key intermediates $\bf{B1}$, $\bf{B2}$, and $\bf{B3}$ for the generation of $\bf{A}$.

The following statements are made:

1. $\bf{A}$ contains a three-membered ring.

2. $\bf{B1}$ contains a benzyne structure.

3. $\bf{B2}$ has five rings.

4. The number of aromatic rings in $\bf{B3}$ is the same as that in $\bf{B2}$.

Select the option below that contains all the correct statements:
二苯基环丙烯酮可以发生如下反应：

<MultiModal>![`COC1=CC(OS(=O)(C(F)(F)F)=O)=C([Si](C)(C)C)C=C1OC`和`O=C1C(C2=CC=CC=C2)=C1C3=CC=CC=C3`在乙腈中与氟化铯反应生成$\bf{A}$，$\bf{A}$在$TfOH$作用下生成`COC1=C(OC)C=C(C(/C(C2=CC=CC=C2)=C\C3=CC=CC=C3)=C(C=C(OC)C(OC)=C4)C4=[O+]5)C5=C1`](/media/uploads/c0ce34a9-b607-4fb9-932e-bde700f4ce33.png)</MultiModal>

考察$\bf{A}$的结构简式和生成$\bf{A}$的三个关键中间体$\bf{B1}$、$\bf{B2}$和$\bf{B3}$的结构。

有以下说法：

1.$\bf{A}$中具有三元环

2.$\bf{B1}$含苯炔结构

3.$\bf{B2}$中有五个环

4.$\bf{B3}$中芳香环的数量与$\bf{B2}$中相同

选出以下选项中包含全部正确说法的一项：
All other options are incorrect
1
2
3
4
1,2
1,3
1,4
2,3
2,4
3,4
1,2,3
1,2,4
1,3,4
2,3,4
1,2,3,4
其他选项均不正确
1
2
3
4
1,2
1,3
1,4
2,3
2,4
3,4
1,2,3
1,2,4
1,3,4
2,3,4
1,2,3,4
The product is a positive ion, which is easily understood to be produced by protonation with $TfOH$. Observing the product structure, a hydrogen appears on the $sp^2$ carbon where the exocyclic double bond is bonded to a phenyl group, which should be generated by protonation. Therefore, $\bf{A}$: `COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`

<Checkpoint>[The structure of $\bf{A}$ is: `COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`, containing a three-membered ring, statement 1 is correct](1)</Checkpoint>

To study the process of generating $\bf{A}$, cesium fluoride first removes the silyl group from the raw material `COC1=CC(OS(=O)(C(F)(F)F)=O)=C([Si](C)(C)C)C=C1OC` to generate a negative ion, and then $TfO^-$ is removed to generate benzyne, i.e., $\bf{B1}$: `COC1=CC#CC=C1OC`

<Checkpoint>[The structure of $\bf{B1}$ is `COC1=CC#CC=C1OC`, containing benzyne, statement 2 is correct](1)</Checkpoint>

The diphenylcyclopropenone of the raw material can be considered to have a charge-separated structure:

<MultiModal>![`[O-][C+]1C(C2=CC=CC=C2)=C1C3=CC=CC=C3`](/media/uploads/dea3a8f8-1b92-428f-a921-279883363632.png)</MultiModal>

It reacts with the generated benzyne to form a ring to obtain $\bf{B2}$: `COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`.

<Checkpoint>[The structure of $\bf{B2}$ is `COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`, with 5 rings, statement 3 is correct](1)</Checkpoint>

Then the unstable benzocyclobutene ring opens to obtain $\bf{B3}$: `COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`

<Checkpoint>[The structure of $\bf{B3}$ is `COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`, which has two benzene rings and two aromatic rings, one less than in $\bf{B2}$, statement 4 is incorrect](1)</Checkpoint>

Then $\bf{B3}$ undergoes a Diels-Alder reaction with another molecule of $\bf{B1}$ to obtain $\bf{A}$.

Statements 1, 2, and 3 are correct, choose L

<MultiModal>![$\bf{A}$：`COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`；$\bf{B1}$：`COC1=CC#CC=C1OC`；$\bf{B2}$：`COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`；$\bf{B3}$：`COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`](/media/uploads/1ec4842a-52bc-4c1a-b934-c817a66bfb10.png)</MultiModal>
产物为一正离子，易知是经$TfOH$质子化产生。观察产物结构，在环外双键与一个苯基成键的$sp^2$碳上出现了一个氢，应为质子化产生，则$\bf{A}$：`COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`

<Checkpoint>[$\bf{A}$的结构为：`COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`，含有三元环，说法1正确](1)</Checkpoint>

研究生成$\bf{A}$的过程，首先氟化铯使原料`COC1=CC(OS(=O)(C(F)(F)F)=O)=C([Si](C)(C)C)C=C1OC`中的硅基离去产生负离子，随后再离去$TfO^-$，产生苯炔，即$\bf{B1}$：`COC1=CC#CC=C1OC`

<Checkpoint>[$\bf{B1}$的结构为`COC1=CC#CC=C1OC`，含有苯炔，说法2正确](1)</Checkpoint>

原料的二苯基环丙烯酮可认为存在电荷分离的结构：

<MultiModal>![`[O-][C+]1C(C2=CC=CC=C2)=C1C3=CC=CC=C3`](/media/uploads/dea3a8f8-1b92-428f-a921-279883363632.png)</MultiModal>

与产生的苯炔反应成环得到$\bf{B2}$：`COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`。

<Checkpoint>[$\bf{B2}$的结构为`COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`，有5个环，说法3正确](1)</Checkpoint>

随后不稳定的苯并四元环开环，得到$\bf{B3}$：`COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`

<Checkpoint>[$\bf{B3}$的结构为`COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`，其中有两个苯环，有两个芳香环，数量比$\bf{B2}$中少一个，说法4错误](1)</Checkpoint>

随后$\bf{B3}$与另一分子$\bf{B1}$发生Diels-Alder反应，得到$\bf{A}$。

说法1，2，3正确，选L

<MultiModal>![$\bf{A}$：`COC1=C(OC)C=C(C2(C(C3=CC=CC=C3)=C2C4=CC=CC=C4)C(C=C(OC)C(OC)=C5)=C5O6)C6=C1`；$\bf{B1}$：`COC1=CC#CC=C1OC`；$\bf{B2}$：`COC1=CC2=C(C3(C(C4=CC=CC=C4)=C3C5=CC=CC=C5)O2)C=C1OC`；$\bf{B3}$：`COC(C(OC)=C/C1=C2C(C3=CC=CC=C3)=C\2C4=CC=CC=C4)=CC1=O`](/media/uploads/1ec4842a-52bc-4c1a-b934-c817a66bfb10.png)</MultiModal>