各位化学同仁：
秋意阑珊，凛冬将至。庚子之年，转瞬即逝，有机合成路线设计擂台赛也陪伴大家度过了第三个春秋。掩上过往的重门，背负起故事的行囊，想必大家感慨万千，而在放逐绿色的季节，光阴如是，有增无减。此去过往，就托付给尘封的历史。宠辱得失，皆为序章，道阻且长，行则将至。
药明康德化学技术部为大家悉心整理了2020年最后一期的擂台赛试题，敢问大家是否已在日复一日的学习与工作中领会到合成路线设计的精髓？分子千变万化，决策始终如一。文末还附有往期竞赛试题，供君一览。本期试题解析仍旧以网络直播的形式于近日择时分享，敬请关注！
1. 请写出以下多步转化的产物结构（每题4分，最后两题每空2分，共计20分；相对构型需要标注明确）。Please provide the structures of products after multi-step transformations (20 points, 4 points for each and 2 points for each blank in the last two questions; the relative configuration needs to be clearly labeled).
2. 设计两条路线合成以下化合物。注意：苯环原料最多有两个取代基（20分）。
Please propose two reasonable synthetic routes to synthesize below target starting from commercially available reagents. Note: The benzene ring material can only have two substituents at most (20 points).
3. 使用不同的关环策略设计两条路线合成以下化合物。注意：芳环原料最多有三个取代基（20分）。Please propose two reasonable synthetic routes to synthesize below target starting from commercially available reagents by two different ring closure strategies. Note: The aromatic ring material can only have three substituents at most (20 points).
4. 设计两条路线合成以下化合物，其中一条路线要合成五元环，另一条路线要合成六元环（20分）。Please propose two reasonable synthetic routes to synthesize below target starting from commercially available reagents (one route via closure of five-membered ring strategy and the other one via closure of six-membered ring) (20 points).
Please propose two reasonable synthetic route to synthesize below racemic target starting from commercially available reagents (20 points).
Please propose one reasonable synthetic route to synthesize below chiral target (20 points).
