Synthesis of some new highly functionalized C6-synthons
摘要:
Starting with epsilon-caprolactone a new synthesis of methyl 6-hydroxy-2-hexenoate, 2a, is described. The preparation of the new highly functionalized CB-synthons methyl 6-acyloxy-4-oxo-2-hexenoates, 1b and 1c, methyl 6-benzoyloxy-4-hydroxy-2-hexenoate, 13, and methyl 6-benzoyloxy-4-oxohexanoate, 14, is also reported.
Diverse<i>N</i>-Heterocyclic Ring Systems via Aza-Heck Cyclizations of<i>N</i>-(Pentafluorobenzoyloxy)sulfonamides
作者:Ian R. Hazelden、Xiaofeng Ma、Thomas Langer、John F. Bower
DOI:10.1002/anie.201605152
日期:2016.9.5
bond of N‐(pentafluoro‐benzoyloxy)sulfonamides are described. These studies, which encompass only the second class of aza‐Heck reaction developed to date, provide direct access to diverse N‐heterocyclicringsystems.
Pyrrolidines and Piperidines by Ligand-Enabled Aza-Heck Cyclizations and Cascades of <i>N</i>
-(Pentafluorobenzoyloxy)carbamates
作者:Ian R. Hazelden、Rafaela C. Carmona、Thomas Langer、Paul G. Pringle、John F. Bower
DOI:10.1002/anie.201801109
日期:2018.4.23
Ligand‐enabled aza‐Heck cyclizations and cascades of N‐(pentafluorobenzoyloxy)carbamates are described. These studies encompass the first examples of efficient non‐biased 6‐exo aza‐Heck cyclizations. The methodology provides direct and flexible access to carbamate protected pyrrolidines and piperidines.
Stereospecific Alkene Aziridination Using a Bifunctional Amino-Reagent: An Aza-Prilezhaev Reaction
作者:Joshua J. Farndon、Tom A. Young、John F. Bower
DOI:10.1021/jacs.8b10485
日期:2018.12.26
deprotection (TFA) of O-Ts activated N-Boc hydroxylamines triggers intramolecular aziridination of N-tethered alkenes to provide complex N-heterocyclic ring systems. Synthetic and computational studies corroborate a diastereospecific aza-Prilezhaev-type mechanism. The feasibility of related intermolecular alkene aziridinations is also demonstrated.
Intramolecular [4 + 3] cycloadditions – Stereochemical issues in the cycloaddition reactions of cyclopentenyl cations – A synthesis of (+)-dactylol
作者:Michael Harmata、Paitoon Rashatasakhon、Charles L Barnes
DOI:10.1139/v06-122
日期:2006.10.1
Five cyclopentanones were prepared for the purpose of examining the effects of stereogenic centers on the course of the intramolecular [4 + 3] cycloaddition reactions of cyclopentenyl cations. One substrate reacted with very high levels of diastereoselectivity and was converted to (+)-dactylol. The cyclopentenone without stereogenic centers on the tether or the five-membered ring gave two cycloadducts
Intramolecular Simmons−Smith Cyclopropanation. Studies into the Reactivity of Alkyl-Substituted Zinc Carbenoids, Effect of Directing Groups and Synthesis of Bicyclo[<i>n</i>.1.0]alkanes
作者:James A. Bull、André B. Charette
DOI:10.1021/ja907504w
日期:2010.2.17
explored. Substitution on the alkene and at the allylic position was well tolerated, providing the bicyclic products in high yields. Additionally, the IMSS reaction allowed a highly diastereoselective synthesis of a 5-3-5 fused tricycloalkane. These studies will have implications for the use of substituted carbenoids in cyclopropanation reactions and for directed cyclopropanation reactions as well as in
已经开发了分子内 Simmons-Smith (IMSS) 环丙烷化,为构建取代的双环烷烃提供了一种新方法。首先,以高收率制备了含有烯丙醇的功能化的偕二碘烷烃。然后研究了分子内环化形成不同环大小的过程,并证明可以成功合成双环[3.1.0]己烷和双环[4.1.0]庚烷。更大的链长导致含末端烯烃的产物。Analysis of the product distribution for the different ring sizes and under various reaction conditions provided insight into the reactivity of substituted zinc carbenoids, and by the appropriate choice of conditions cyclopropanation could be promoted