Here are two reactions:

Reaction 1: <MultiModal>![CC1(CC(C2=C(SCCCC([R1])C2)C1)=O)C>[R]S.[DBU]>，followed by the addition of TFA to obtain the product](/media/uploads/5b75482b-e7e4-43f6-aa72-322d41a4bd64.png)</MultiModal>

Reaction 2: <MultiModal>![C=C1C(OCCCCCCCCOC(CSC1C2=CC=CC=C2)=O)=O>[1%DBU].[DMF].[r.t.]>](/media/uploads/c9d9df08-49ea-4af8-bf24-ef4662ddc947.png)</MultiModal>

What are the products of the two reactions, respectively?
下面有两个反应

反应1：<MultiModal>![CC1(CC(C2=C(SCCCC([R1])C2)C1)=O)C>[R]S.[DBU]>，随后加入TFA得到产物](/media/uploads/5b75482b-e7e4-43f6-aa72-322d41a4bd64.png)</MultiModal>

反应2：<MultiModal>![C=C1C(OCCCCCCCCOC(CSC1C2=CC=CC=C2)=O)=O>[1%DBU].[DMF].[r.t.]>](/media/uploads/c9d9df08-49ea-4af8-bf24-ef4662ddc947.png)</MultiModal>

下面说法正确的是？
Reaction 1 involves a key intermediate: <MultiModal>![CC1(CC(C2C(SCCCC([R1])C2)(S[R])C1)=O)C](/media/uploads/cc9c212a-b756-42de-b24e-2e5e9207280b.png)</MultiModal>
Reaction 1 has a key intermediate: <MultiModal>![CC1(CC(C(CC([R1])CCCS[R])C([S-])C1)=O)C](/media/uploads/2ea1e78d-9077-461d-a3fb-0a38bead61a4.png)</MultiModal>
Possible by-products of reaction 1: <MultiModal>![CC1(CC(C(CC([R1])CCCS)C(S[R])C1)=O)C](/media/uploads/b81841c6-4d94-49dc-a9d0-2d8c39874035.png)</MultiModal>
The product end group of reaction 1 is uncertain.
The product of reaction 2 is: <MultiModal>![O=C(OCCCCCCCCOC(C[X2])=O)C(CC1=CC=CC=C1)CS[X1]，其中X1和X2是重复单元的连接位点](/media/uploads/e54ebbbd-bb6b-4418-9b11-b1cb4307fa46.png)</MultiModal>
The product of reaction 2 is: <MultiModal>![O=C(OCCCCCCCCOC(C[X2])=O)/C(CS[X1])=C/C1=CC=CC=C1，where X1 and X2 are the connection sites of the repeating unit](/media/uploads/ed85e2bf-d0ba-4c31-bda5-b48f7f8e4b02.png)</MultiModal>
The end group of reaction 2 is defined.
All other options are incorrect.
反应1存在关键中间体：<MultiModal>![CC1(CC(C2C(SCCCC([R1])C2)(S[R])C1)=O)C](/media/uploads/cc9c212a-b756-42de-b24e-2e5e9207280b.png)</MultiModal>
反应1存在关键中间体：<MultiModal>![CC1(CC(C(CC([R1])CCCS[R])C([S-])C1)=O)C](/media/uploads/2ea1e78d-9077-461d-a3fb-0a38bead61a4.png)</MultiModal>
反应1的可能存在副产物：<MultiModal>![CC1(CC(C(CC([R1])CCCS)C(S[R])C1)=O)C](/media/uploads/b81841c6-4d94-49dc-a9d0-2d8c39874035.png)</MultiModal>
反应1的产物端基不确定
反应2的产物为：<MultiModal>![O=C(OCCCCCCCCOC(C[X2])=O)C(CC1=CC=CC=C1)CS[X1]，其中X1和X2是重复单元的连接位点](/media/uploads/e54ebbbd-bb6b-4418-9b11-b1cb4307fa46.png)</MultiModal>
反应2的产物为：<MultiModal>![O=C(OCCCCCCCCOC(C[X2])=O)/C(CS[X1])=C/C1=CC=CC=C1，其中X1和X2是重复单元的连接位点](/media/uploads/ed85e2bf-d0ba-4c31-bda5-b48f7f8e4b02.png)</MultiModal>
反应2的端基是确定的
其他选项均不正确
Reaction 1 is a ring-opening polymerization reaction. DBU, as a strong base, deprotonates RSH to generate a thiolate anion, which then undergoes 1,4-addition to the alpha-beta unsaturated ketone substrate, yielding an enolate intermediate 1. This intermediate undergoes ring-opening to form a thiolate anion intermediate 2. Subsequently, intermediate 2 repeats this process to complete the polymerization. TFA is used to quench the reaction, and the end groups of the product of reaction 1 are RS and H.

<MultiModal>![给人看的](/media/uploads/2df881a0-4675-40fc-b1a0-5431b43aa2e1.png)</MultiModal>

<Checkpoint>[DBU使RSH去质子化](1)</Checkpoint>

<Checkpoint>[硫醇负离子对底物alpha-beta不饱和酮进行1,4-加成](1)</Checkpoint>

<Checkpoint>[反应1的关键中间体1为CC1(CC([O-])=C2C(SCCCC([R1])C2)(S[R])C1)C](1)</Checkpoint>

<Checkpoint>[反应1的关键中间体2为CC1(CC(C(CC([R1])CCC[S-])=C(S[R])C1)=O)C](1)</Checkpoint>

Therefore, the structure of option A is not a key intermediate in reaction 1, the R group position in option B is incorrect, the six-membered ring in option C is missing a double bond, D is incorrect, and the end groups are determined.

<Checkpoint>[A的结构不是反应1的关键中间体](0.5)</Checkpoint>

<Checkpoint>[B结构R基位置错误](1)</Checkpoint>

<Checkpoint>[C的结构六元环缺少双键](1)</Checkpoint>

Reaction 2 is a ring-opening polymerization reaction. DBU undergoes 1,4-addition to the alpha-beta unsaturated ketone substrate, yielding an enolate intermediate 1. This intermediate undergoes ring-opening to form a thiolate anion intermediate 2. Subsequently, intermediate 2 repeats this process to complete the polymerization. The end groups of the product are uncertain.

<Checkpoint>[DBU对对底物alpha-beta不饱和酮进行1,4-加成](1)</Checkpoint>

<Checkpoint>[反应2的产物为O=C(OCCCCCCCCOC(C[X2])=O)/C(CS[X1])=C/C1=CC=CC=C1，其中X1和X2是重复单元的连接位点](1)</Checkpoint>

The repeating unit structure in option E is incorrect, with an extra S and missing a C-C double bond. Option F is correct, and option G is incorrect. The end groups are uncertain.

<Checkpoint>[E结构重复单元多了一个S原子，少了一个C-C双键](1)</Checkpoint>
反应1为开环聚合反应，DBU作为强碱使RSH去质子化生成硫醇负离子对底物alpha-beta不饱和酮进行1,4-加成得到烯醇负离子中间体1，该中间体开环得到硫醇负离子中间体2，随后中间体2重复该过程完成聚合，TFA用于淬灭反应，反应1产物的端基为RS和H。

<MultiModal>![给人看的](/media/uploads/2df881a0-4675-40fc-b1a0-5431b43aa2e1.png)</MultiModal>

<Checkpoint>[DBU使RSH去质子化](1)</Checkpoint>

<Checkpoint>[硫醇负离子对底物alpha-beta不饱和酮进行1,4-加成](1)</Checkpoint>

<Checkpoint>[反应1的关键中间体1为CC1(CC([O-])=C2C(SCCCC([R1])C2)(S[R])C1)C](1)</Checkpoint>

<Checkpoint>[反应1的关键中间体2为CC1(CC(C(CC([R1])CCC[S-])=C(S[R])C1)=O)C](1)</Checkpoint>

因此，选项A的结构不是反应1的关键中间体，选项B结构R基位置错误，选项C六元环缺少双键，D错误，端基确定

<Checkpoint>[A的结构不是反应1的关键中间体](0.5)</Checkpoint>

<Checkpoint>[B结构R基位置错误](1)</Checkpoint>

<Checkpoint>[C的结构六元环缺少双键](1)</Checkpoint>

反应2为开环聚合反应，DBU对对底物alpha-beta不饱和酮进行1,4-加成得到烯醇负离子中间体1，该中间体开环得到硫醇负离子中间体2，随后中间体2重复该过程完成聚合，产物的端基不确定。

<Checkpoint>[DBU对对底物alpha-beta不饱和酮进行1,4-加成](1)</Checkpoint>

<Checkpoint>[反应2的产物为O=C(OCCCCCCCCOC(C[X2])=O)/C(CS[X1])=C/C1=CC=CC=C1，其中X1和X2是重复单元的连接位点](1)</Checkpoint>

选项E重复单元结构错误，少了一个C-C双键，选项F正确，选项G错误，端基不确定

<Checkpoint>[E结构重复单元少了一个C-C双键](1)</Checkpoint>