Rearrangements of Substituted 3-Aza-1,2,5-hexatrienes. 3. The Scope and Versatility of an Extremely Mild 3-Aza-Cope Reaction
摘要:
An investigation of the [3,3]-sigmatropic reaction of substituted 3-aza-1,2,5-hexatrienes to give 4-pentenenitriles is presented. This reaction has been found to occur under a wide variety of reactions conditions (10 are reported) starting from readily available N-allylamides. In contrast to other 3-aza-Cope reactions, this process occurs at room temperature, under essentially neutral conditions, allowing for the facile preparation of substituted nitrile products in moderate to excellent yields. The scope and versatility of this reaction are demonstrated by its use on a wide variety of substrates, including nitrogen- and oxygen-substituted amides. The rearrangements of cis- and trans-4-tert-butyl-N-allylcyclohexanecarboxamides 16a and 16b are reported and were found to give a ratio of axial to equatorial (A:E) products consistent with A:E ratios found for other related sigmatropic reactions. The stereochemical requirements for this reaction appear to be similar to other [3,3]-rearrangements even though the transition state for this rearrangement is most likely neither boat nor chairlike.
Reaction of the quaternary ammonium salts 2a–i with electrophilic alkenes 3, active alkylating agents 7 or aromatic aldehydes 11, carried out in basic two-phase systems A–D, afforded cyclopropanes 4, cyanoalkenes 8 or cyanooxiranes 12 respectively, via the corresponding ammoniumylides 2+ –. The method is very simple, and gives cyclopropanes 4 and cyanoalkenes 8 in high yield. Under similar conditions
Generation and Reactions of Ammonium Ylides in Basic Two-Phase Systems: Convenient Synthesis of Cyclopropanes, Oxiranes and Alkenes Substituted with Electron-Withdrawing Groups
作者:Andrzej Jończyk、Anna Konarska
DOI:10.1055/s-1999-2757
日期:1999.7
Direct access to pentenedinitriles <i>via</i> Ni-catalyzed dihydrocyanation of 1,3-enynes
作者:Feilong Sun、Jihui Gao、Xianjie Fang
DOI:10.1039/d0cc02938f
日期:——
A highly regio- and stereoselective dihydrocyanation of 1,3-enynes was implemented by nickel/diphosphine catalysts.
1,3-烯烃的高区域和立体选择性二氢氰化反应由镍/二膦催化剂实现。
Rearrangements of Substituted 3-Aza-1,2,5-hexatrienes. 3. The Scope and Versatility of an Extremely Mild 3-Aza-Cope Reaction
作者:Michael A. Walters、Andrew B. Hoem、Colleen S. McDonough
DOI:10.1021/jo951587g
日期:1996.1.1
An investigation of the [3,3]-sigmatropic reaction of substituted 3-aza-1,2,5-hexatrienes to give 4-pentenenitriles is presented. This reaction has been found to occur under a wide variety of reactions conditions (10 are reported) starting from readily available N-allylamides. In contrast to other 3-aza-Cope reactions, this process occurs at room temperature, under essentially neutral conditions, allowing for the facile preparation of substituted nitrile products in moderate to excellent yields. The scope and versatility of this reaction are demonstrated by its use on a wide variety of substrates, including nitrogen- and oxygen-substituted amides. The rearrangements of cis- and trans-4-tert-butyl-N-allylcyclohexanecarboxamides 16a and 16b are reported and were found to give a ratio of axial to equatorial (A:E) products consistent with A:E ratios found for other related sigmatropic reactions. The stereochemical requirements for this reaction appear to be similar to other [3,3]-rearrangements even though the transition state for this rearrangement is most likely neither boat nor chairlike.