Under microwave (MW) promotion and imidazole (Imidazole) catalysis, the following compound reacts in a closed vessel and xylenes to obtain a product containing a benzene ring, as shown in Figure 1:

<MultiModal>![Fig. 1, the reaction in the figure is described by SMILES as: CC(C)(C#CC1(O/C=C/C(OC)=O)C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C>>C[C@@]5(CCC[C@@]6(C)C(OC)=O)C6CC[C@@]78C(C(O)=C(C=O)C(C(C)(C)C)=C9)=C9[C@](C)(C8)CCC57, where the reaction conditions are microwave [1h, 190°C], imidazole (10 mol%), closed vessel, xylenes](/media/uploads/26f59578-0f18-43e7-8c22-704bad78ed62.png)</MultiModal>

Please deduce the reaction mechanism and the structure of key intermediates in the reaction process. The following statements are available:

1.  An intramolecular nucleophilic addition reaction occurs in one step during the reaction.
2.  The number of carbon-carbon single bond cleavages in the entire reaction process is one.
3.  The number of carbon-carbon single bond formations in the entire reaction process is two.
4.  A concerted carbon-oxygen single bond cleavage and carbon-carbon single bond formation occur in one step.

Based on your deduced reaction mechanism and the structure of key intermediates, the following options in which all statements are correct and the number of correct statements is the largest are:
在微波(MW)促进、咪唑(Imidazole)催化下,以下化合物在封管(closed vessel)、二甲苯(Xylenes)中反应,得到含苯环的产物，如图1：

<MultiModal>![Fig. 1，图中反应以SMILES描述为：CC(C)(C#CC1(O/C=C/C(OC)=O)C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C>>C[C@@]5(CCC[C@@]6(C)C(OC)=O)C6CC[C@@]78C(C(O)=C(C=O)C(C(C)(C)C)=C9)=C9[C@](C)(C8)CCC57，其中反应条件为微波[1h, 190°C]、咪唑（10 mol%）、封管、二甲苯](/media/uploads/26f59578-0f18-43e7-8c22-704bad78ed62.png)</MultiModal>

请推测反应机理和反应过程中的关键中间体结构。现有以下说法：

1. 反应过程中发生了一步分子内亲核加成反应
2. 整个反应过程中碳碳单键断裂次数为一次
3. 整个反应过程中碳碳单键形成次数为两次
4. 发生了一步协同的碳氧单键断裂和碳碳单键形成

请结合你推测的反应机理与关键中间产物结构，以下选项中说法全部正确且正确说法数量最多的为：
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
Observing the reaction in the figure, the reaction condition is high temperature, and the structural change of the product mainly occurs on the rightmost side, with a large change in the position of the carbon-carbon bond. It is very likely that a rearrangement reaction with a pericyclic mechanism has occurred. Comparing the structures of the reactants and products, it can be found that one or both carbon-oxygen bonds of the ether oxygen atom are partially or completely broken during the reaction. The two hydrogen atoms of the methylene group adjacent to the carbon-oxygen bond on the seven-membered ring disappear in the product, and the methylene group does not have an adjacent carbonyl group or other obvious reactivity. According to the above characteristics, it can be found that a carbon-oxygen bond can undergo a [3, 3] sigma migration under heating to obtain the intermediate in Figure 2:

<MultiModal>![Fig. 2, the molecule in the figure is described by SMILES as: CC(C)(C(C(C=O)C(OC)=O)=C=C1C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/58eaef5e-c3ac-40a8-8de3-8d767daecf7c.png)</MultiModal>

<Checkpoint>[Occurring [3, 3]sigma migration to obtain the intermediate in Figure 2: <MultiModal>![Fig. 2, the molecule in the figure is described by SMILES as: CC(C)(C(C(C=O)C(OC)=O)=C=C1C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/58eaef5e-c3ac-40a8-8de3-8d767daecf7c.png)</MultiModal>](1)</Checkpoint>

This intermediate has an unstable connected carbon-carbon double bond, which can be quickly rearranged into a stable conjugated double bond to obtain the intermediate in Figure 3:

<MultiModal>![Fig. 3, the molecule in the figure is described by SMILES as: CC(C)(/C(C(C=O)C(OC)=O)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/fdab965b-9eac-403c-9f46-27c1e9bb0fe2.png)</MultiModal>

<Checkpoint>[Unstable connected carbon-carbon double bond rearranged into a stable conjugated double bond to obtain the intermediate in Figure 3: <MultiModal>![Fig. 3, the molecule in the figure is described by SMILES as: CC(C)(/C(C(C=O)C(OC)=O)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/fdab965b-9eac-403c-9f46-27c1e9bb0fe2.png)</MultiModal>](1)</Checkpoint>

In order to construct the benzene ring in the product, a carbon-carbon bond also needs to be formed on the double bond carbon of the seven-membered ring. Observing the structure of the intermediate in Figure 3, it can be found that two of the three carbon-carbon double bonds of the benzene ring structure already exist. In fact, the ester group can undergo enolization to provide the third carbon-carbon double bond, as shown in Figure 4:

<MultiModal>![Fig. 4, the molecule in the figure is described by SMILES as: CC(C)(C(/C(C=O)=C(O)\OC)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/8fc80957-1604-44d1-876c-d769b611b132.png)</MultiModal>

In fact, it is already obvious that there are three conjugated carbon-carbon double bonds in the molecule, which can undergo a step of electrocyclic reaction to obtain the benzene ring skeleton, as shown in Figure 5:

<MultiModal>![Fig. 5, the molecule in the figure is described by SMILES as: CC(C)(C(C=C1[C@](C)(C2)CCC3[C@](C)(CCC[C@@]4(C)C(OC)=O)C4CC[C@@]32C1C(O)5OC)=C5C=O)C](/media/uploads/09288f37-5874-4ce6-a3b8-52aef3b11e27.png)</MultiModal>

<Checkpoint>[Ester group enolization to obtain a conjugated triene, electrocyclic reaction to obtain the intermediate in Figure 5: <MultiModal>![Fig. 5, the molecule in the figure is described by SMILES as: CC(C)(C(C=C1[C@](C)(C2)CCC3[C@](C)(CCC[C@@]4(C)C(OC)=O)C4CC[C@@]32C1C(O)5OC)=C5C=O)C](/media/uploads/09288f37-5874-4ce6-a3b8-52aef3b11e27.png)</MultiModal>](1)</Checkpoint>

The hemiacetal structure loses one molecule of methanol, and the resulting carbonyl group undergoes a step of enol isomerization, that is, aromatization to obtain the final product structure.

<Checkpoint>[Removal of methanol, carbonyl isomerization completes aromatization to obtain the final product](1)</Checkpoint>

No nucleophilic addition reaction occurred in the reaction, so statement 1 is incorrect. No carbon-carbon single bond cleavage occurred, so statement 2 is incorrect. Carbon-carbon single bonds are formed once in the first step of [3, 3] sigma migration and once in the electrocyclization, so statement 3 is correct. During the [3, 3] sigma migration, a concerted cleavage of a carbon-oxygen single bond and formation of a carbon-carbon single bond occurred, so statement 4 is correct.
观察图中反应，反应条件为高温，且产物结构变化主要发生在最右侧，碳碳键位置变化较大，很有可能发生了周环反应机理的重排反应。对比反应物和产物结构，可以发现醚氧原子的两根碳氧键反应中发生部分或全部断裂，七元环上与碳氧键相邻的亚甲基两个氢原子在产物中均消失，而该亚甲基没有邻位羰基等明显反应性。根据以上特征，可以发现一根碳氧键恰好可以在加热下发生[3, 3]sigma迁移，得到图2中间体：

<MultiModal>![Fig. 2，图中分子以SMILES描述为：CC(C)(C(C(C=O)C(OC)=O)=C=C1C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/58eaef5e-c3ac-40a8-8de3-8d767daecf7c.png)</MultiModal>

<Checkpoint>[发生[3, 3]sigma迁移，得到图2中间体：<MultiModal>![Fig. 2，图中分子以SMILES描述为：CC(C)(C(C(C=O)C(OC)=O)=C=C1C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/58eaef5e-c3ac-40a8-8de3-8d767daecf7c.png)</MultiModal>](1)</Checkpoint>

该中间体有一个不稳定的相连碳碳双键，可以快速重排成稳定的共轭双键，得到图3中间体：

<MultiModal>![Fig. 3，图中分子以SMILES描述为：CC(C)(/C(C(C=O)C(OC)=O)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/fdab965b-9eac-403c-9f46-27c1e9bb0fe2.png)</MultiModal>

<Checkpoint>[不稳定的相连碳碳双键重排成稳定的共轭双键，得到图3中间体：<MultiModal>![Fig. 3，图中分子以SMILES描述为：CC(C)(/C(C(C=O)C(OC)=O)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/fdab965b-9eac-403c-9f46-27c1e9bb0fe2.png)</MultiModal>](1)</Checkpoint>

为了构建产物中的苯环，还需要在七元环双键碳上形成一根碳碳键。观察图3中间体结构可以发现，苯环结构的三根碳碳双键已经有了两根，实际上酯基可以发生烯醇化提供第三根碳碳双键，如图4：

<MultiModal>![Fig. 4，图中分子以SMILES描述为：CC(C)(C(/C(C=O)=C(O)\OC)=C/C1=C[C@]23CCC4[C@@](CCC[C@@]4(C)C(OC)=O)(C2CC[C@]1(C3)C)C)C](/media/uploads/8fc80957-1604-44d1-876c-d769b611b132.png)</MultiModal>

其实已经很明显，分子内存在三根共轭的碳碳双键，可以发生一步 $6\pi$ 电关环反应得到苯环骨架，如图5：

<MultiModal>![Fig. 5，图中分子以SMILES描述为：CC(C)(C(C=C1[C@](C)(C2)CCC3[C@](C)(CCC[C@@]4(C)C(OC)=O)C4CC[C@@]32C1C(O)5OC)=C5C=O)C](/media/uploads/09288f37-5874-4ce6-a3b8-52aef3b11e27.png)</MultiModal>

<Checkpoint>[酯基烯醇化，得到共轭三烯，$6\pi$ 电关环得到图5中间体：<MultiModal>![Fig. 5，图中分子以SMILES描述为：CC(C)(C(C=C1[C@](C)(C2)CCC3[C@](C)(CCC[C@@]4(C)C(OC)=O)C4CC[C@@]32C1C(O)5OC)=C5C=O)C](/media/uploads/09288f37-5874-4ce6-a3b8-52aef3b11e27.png)</MultiModal>](1)</Checkpoint>

半缩醛结构脱去一份子甲醇，得到的羰基发生一步烯醇异构化即芳构化得到最终产物结构。

<Checkpoint>[脱去甲醇，羰基异构化完成芳构化，得到最终产物](1)</Checkpoint>

反应中没有发生亲核加成反应，说法1错误。没有发生碳碳单键断裂，说法2错误。碳碳单键分别在第一步[3, 3]sigma迁移形成一次，在电环化形成一次，说法3正确。[3, 3]sigma迁移时发生了一步协同的碳氧单键的断裂和碳碳单键形成，说法4正确。