N-Propargylamides via the Asymmetric Michael Addition of B-Alkynyl-10-TMS-9- borabicyclo[3.3.2]decanes to N-Acylimines
摘要:
The asymmetric synthesis of N-propargylamides through Michael addition of the alkynylborane 1 to N-acylimines is reported. The N-acetylimines provide the best substrates for the process exhibiting high selectivity (56-95% ee) with predictable stereochemistry. In several cases, 5 crystallizes in essentially pure form (97-99% ee) and a single-crystal X-ray structure was also obtained for 5g (R-1 = R-2 = Me, R-3 = o-Cl-C6C4). The process regenerates 4 for its direct conversion back to 1 and facilitates the efficient recovery of the pseudoephedrine.
Highly Diastereoselective and Enantioselective Preparation of Homoallylic Amines: Application for the Synthesis of β-Amino Acids and γ-Lactams
作者:P. Veeraraghavan Ramachandran、Thomas E. Burghardt
DOI:10.1002/chem.200401295
日期:2005.7.18
furnished homoallylic amines in good yields and high ee. A 11B NMR spectroscopy study revealed that the reactions do not proceed, even at room temperature, unless a molar equivalent of water or methanol is added. The first reagent-controlled asymmetric crotylboration and alkoxyallylboration of aldimines furnishing beta-methyl or beta-alkoxy homoallylic amines in very high diastereoselectivity and enantioselectivity
New Generation of Highly Reactive Allylborating Agents For Cu(I)-Catalyzed Allylation of Chiral Sulfinylimines
作者:Michael S. Alexeev、Tatyana V. Strelkova、Michail M. Ilyin, Jr.、Yulia V. Nelyubina、Ivan A. Bespalov、Michael Medvedev、Victor N Khrustalev、Nikolai Kuznetsov
DOI:10.1039/d4ob00291a
日期:——
active reagents is an attractive strategy that meets the modern principles of sustainable development of chemistry. In the current study, we for the first time describe the method and general principles of Cu(I)-catalyzed allylation of imines with amine adducts of allylic triorganoboranes. Triallylborane is an extremely reactive compound and cannot be used for the catalytic allylation of imines, whereas
使用高活性试剂实施选择性催化过程是一种有吸引力的策略,符合化学可持续发展的现代原则。在本研究中,我们首次描述了Cu( I )催化亚胺与烯丙基三有机硼烷胺加合物的烯丙基化反应的方法和一般原理。三烯丙基硼烷是一种极其活泼的化合物,不能用于亚胺的催化烯丙基化,而其胺加合物是理想的催化底物。胺片段的结构成功地平衡了烯丙基硼试剂的安全性、选择性和稳定性,使其在催化烯丙基化反应中表现出高活性,超过任何已知的烯丙基硼烷许多倍。获得的结果得到定量动力学数据和 DFT 计算的支持。该系统的催化功效在亚磺酰亚胺模型(23 个例子)上得到了证明。实现了高达 >99% 的高非对映选择性,包括克级合成 2-羟基苯基衍生物。考虑到三烯基硼烷(AAT)的胺加合物的高反应活性和无与伦比的原子经济性,它们可以被认为是Cu( I )和其他合适金属催化剂的潜在烯丙基化试剂。
The Critical Importance of Water in the Asymmetric Allylboration ofN-Trimethylsilylbenzaldimines withB-Allyldiisopinocampheylborane
作者:Guang-Ming Chen、P. Veeraraghavan Ramachandran、Herbert C. Brown
The free aldimine is probably the intermediate in the asymmetric allylboration of N-trimethylsilylaldimines in the presence of water (see scheme), which is critical for the reaction. The aldimine is rapidly captured by the allylborating agent. Ipc2 BAll=B-allyldiisopinocampheylborane.
<i>N</i>-Propargylamides via the Asymmetric Michael Addition of <i>B</i>-Alkynyl-10-TMS-9- borabicyclo[3.3.2]decanes to <i>N</i>-Acylimines
作者:Ana Z. Gonzalez、Eda Canales、John A. Soderquist
DOI:10.1021/ol0611595
日期:2006.7.1
The asymmetric synthesis of N-propargylamides through Michael addition of the alkynylborane 1 to N-acylimines is reported. The N-acetylimines provide the best substrates for the process exhibiting high selectivity (56-95% ee) with predictable stereochemistry. In several cases, 5 crystallizes in essentially pure form (97-99% ee) and a single-crystal X-ray structure was also obtained for 5g (R-1 = R-2 = Me, R-3 = o-Cl-C6C4). The process regenerates 4 for its direct conversion back to 1 and facilitates the efficient recovery of the pseudoephedrine.
Direct Catalytic Asymmetric Aminoallylation of Aldehydes: Synergism of Chiral and Nonchiral Brønsted Acids
作者:Hong Ren、William D. Wulff
DOI:10.1021/ja1110865
日期:2011.4.20
The development of a catalytic asymmetric method for the direct aminoallylation of aldehydes is described that gives high asymmetric inductions for a broad range of substrates including both aromatic and aliphatic aldehydes. This method allows for direct isolation of unprotected analytically pure homoallylic amines without chromatography. The unique catalyst system developed for this process involves