启发式教学在立体化学手性分子教学中的应用

以有机立体化学中的手性分子教学为例,探讨兴趣启发、重点启发、问题启发和规律启发法等多种启发式教学方法在立体化学教学中的运用,以培养学生发现问题、分析问题、解决问题和创新的能力。     

在“旋光异构”教学中,加强基本概念初探

立体化学是现代有机化学的重要内容。部颁大纲规定,在基础有机中学习立体化学的任务是“初步掌握立体化学的基本知识和基本理论”。就其内容而论,重点是静态立体化学(即分子在基态时的立体异构现象),动态立体化学(即反应过程中,分子运动变化中的立体化学)仅是初窥门径。为了让学生明确学习立体化学的目的,我们举出一些生产和生活实例来说明旋光异构现象的普遍性,藉以说明没有立体化学也就没有有机化学的今天。     

剑桥结构数据库在立体化学教学中的应用实践

应用英国剑桥结构数据库并结合相关三维可视化软件于立体化学中关于构型、构象、手性等概念的教学,增加立体化学教学的直观性和可视性,便于学生对相关知识的理解和掌握。     

基础有机化学教学中同学易混淆的几个立体化学问题

在有机化学的教学中,立体化学部分同学往往感到难以掌握.特别是对于有关环状化合物的顺反异构,光活性异构及环己烷衍生物的构象异构现象,往往概念模糊易于混淆. 一个问题是具有手性碳原子的环状化合物的命名问题.学习了环烷烃之后,同学对环烷烃的命名虽说基本掌握,但从立体化学的角度看却显得有些不完全.如:     

立体化学教学中不对称催化科研成果的融入

在基础有机化学教学中引入不对称催化的概念和科研成果,可将立体化学融入贯穿到有机化学课程的章节教学中,丰富立体化学的教学内容。通过对知识点的串联解析使学生了解不对称催化反应,从而逐步加深对立体化学的理解。组织相关研究方向的学术专题报告和科研实践,不仅有助于巩固相关理论知识,还可以让学生在知识熏陶和实验实践中培养自身的学术素养和科研能力,提高学习热情和积极性。     

有机立体化学教学中手模型的设计与应用

介绍一种通过手势建立＂手模型＂的方法。该法方便、直观、易于掌握,可用于有机立体化学的教学,帮助学生理解有机化合物的立体结构和有机反应的立体化学过程。     

立体化学相关问题及概念解析

立体化学是高校有机化学教学中的一个难点。本文用图示的方式解析了异构体分类问题以及易于混淆的相关概念,明确了立体异构分类方法及各类立体异构体间的从属关系。从宏观和微观两个角度解析了立体化学的相关概念,并探讨了概念间的关联性。     

构象与化学反应性

本文论述了化合物构象与反应性及产物的立体化学关系。列举了十一个不同反应类型的例子,以说明如何从反应机理出发,分析反应过渡态中的立体化学关系,来理解和预测立体异构体表现出来的化学反应性和产物立体化学上的差别。     

立体化学教学中易混淆的一些概念

立体化学教学中易混淆的一些概念彭万华（湖北三峡学院化学系宜昌４４３０００）杨小平谭凤姣（湘潭师范学院化学系４１１１００）自从范荷夫（Ｖａｎ＇ｔＨｏｆ）和勒贝尔（ＬｅＢｅｌ）提出一切分子都具有三维结构的论点以来，立体化学开始迅猛发展，并成为一门独立的学...     

也谈立体化学相关问题及概念解析

简述了国内外有机化学教材中关于立体化学的安排顺序及内容,指出立体化学教学的重要性。对于立体异构体的分类方法提出不同的观点,阐述立体结构的范畴,强调结构与性质的关系等。最后,浅谈教好、学好有机立体化学的方法与体会。     

Application of the AAA reaction to the synthesis of the furanoside of C-2-epi-hygromycin A: a total synthesis of C-2-epi-hygromycin A

A strategy for stereocontrolled syntheses of furanoside type of natural products is developed for a glycosyl aryl ether. This strategy resolves the issue of low diastereoselectivity typical of normal glycosidation methods for furanosides. All the stereochemistry ultimately derives from a desymmetrization of a 2,5-diacyloxy-2,5-dihydrofuran using Pd catalyzed asymmetric allylic alkylation which sets both the absolute stereochemistry and 1,4-relative stereochemistry. Diastereo-controlled elaboration of the 3,4-double bond then completes the synthesis. A new conjunctive reagent, 1-nitro-1-phenylsulfonyl-ethane, is developed to serve as an acyl anion equivalent. The utility of a phenol as a nucleophile in the Pd catalyzed glycosylation is demonstrated. From this strategy emerged a short, practical synthesis of C-2-epi-hygromycin A.     

VESTA软件在典型晶体结构教学中的应用

晶体结构的基本概念既多又抽象,没有较强的空间想象力很难理解和辨析清楚。二维图缺乏空间感;而实物模型只做出一个晶胞,其重复规律不直观。VESTA晶体结构软件能够根据需要构建多个三维晶胞,即超胞,可以很直观地显示出晶体结构的特点。本文通过几个教学实例说明VESTA软件如何帮助学生深入理解晶体结构的基本概念、结构特点与性能的关系,以及拓展晶体结构的认知领域,提高学习兴趣与探索能力。     

A convergent synthesis of the [4.4]-spiroacetal-γ-lactones cephalosporolides E and F

A short convergent synthesis of the fungal metabolites cephalosporolides E and F is reported. The key step makes use of a chelation-controlled Mukaiyama aldol reaction to access the key acyclic spiroacetal precursor with the required syn stereochemistry.     

分析化学在线课堂引入实验视频教学模式改革

The current situation of analytical chemistry teaching and reform, as well as some problems in micro-videos of online classroom was analyzed. In order to solve these problems, short experimental videos were introduced to the online classroom to demonstrate experimental methods. The new teaching mode achieves mutual integration and promotion of the classroom teaching and laboratory teaching, providing opportunities and challenges for the teaching reform of chemistry online course. The results of the teaching reform were investigated and analyzed by questionnaire.     

Synthesis of Dioxa-cage Compounds as a New Probe for the Stereochemistry of the Bisadducts of p-Benzoquinone with 1,3-Cyclodienes

π-Facial stereoselectivety in Diels-alder reactions and their synthetic applications have attracted considerable attention in recent years. In the Diels-Alder reaction of the cyclopentadiene-quinone cycloadduct 1 with cycloalkadiene, four bisadducts with different stereochemistry could potentially result endo-anti-endo 2, endo-antiexo 3, endo-syn-exo 4, and endo-syn-endo 5. Nevertheless, 2 was the only one formed directly in the cycloaddition of 1 with cyclodienes. The π-facial selectivity in Diels-Alderr reactions of compounds 6 and 7 with cyclodienes was reported and the stereochemistry of the cycloadducts was determined by exhausted chemical correlation, spectral comparsion, and x-ray analyses. We report here the synthesis of dioxa-cge compounds 8-11 as a new probe for the determination of the stereochemistry of the bisadducts of p-benzoquinone with cyclodienes. The synthesis of dioxa-cage compounds 8-11 from the bisadducts 2-5 was achieved by a very short sequence. The stereochemistry of the dioxa-cage 8-11 was unambiguously determined by H-H COSY and NOE experiments.     

Synthetic utility of oxyallyls: preparation of an analogue of helminthosporic acid

We describe a synthesis of a novel amino acid resembling helminthosporic acid. The route is short (six steps) and uses oxyallyl methodology to establish the correct regio- and stereochemistry in the required bicyclic system.     

Permanganate oxidation of 1,5,9-trienes: stereoselective synthesis of tetrahydrofuran-containing fragments

Permanganate oxidation of farnesoate esters 12a-d afforded perhydro-2,2'-bifuranyl compounds 16a-d, with control of relative stereochemistry at four new stereocenters. Subsequent oxidative cleavage of 16a-d then provided tetrahydrofuran-containing fragments 17a-d, one of them 17b possessing the same relative stereochemistry present in the C13-C21 portion of the polyether antibiotic semduramycin (1). Control of the absolute stereochemistry was achieved through the use of the Oppolzer sultam chiral auxiliary. The requisite starting trienes were prepared stereoselectively in just three steps from geranyl chloride or neryl chloride, providing a short and versatile route to polyether fragments.     

基于“腾讯会议+课堂派”的有机化学课程在线教学实践

新冠疫情期间,开展在线教学是响应教育部"停课不停学,停课不停教"号召的重要举措,而如何保障在线教学的效果是亟待解决的关键问题。本研究基于"腾讯会议+课堂派"平台,辅以其他过程性评价平台,从重组教学资源、创新教学活动、重整教学评价三个维度,构建有机化学课程的在线教学新模式,为有效实施在线教学提供参考。