[EN] CIS-2,6-DISUBSTITUTED TETRAHYDROPYRAN DERIVATIVES AND PREPARATION METHOD THEREOF [FR] DÉRIVÉS DE TÉTRAHYDROPYRANE CIS-2,6-DISUBSTITUÉS ET PROCÉDÉ POUR LES PRÉPARER
Arene-catalysed lithiation of triflates and triflamides under barbier-type conditions: An indirect transformation of alcohols and amines into organolithium compounds
作者:Emma Alonso、Diego J Ramón、Miguel Yus
DOI:10.1016/0040-4020(96)00886-1
日期:1996.11
The reaction of alkyl triflates 1 or allyl or benzyl triflamides 3 with an excess of lithium powder and a catalytic amount of naphthalene (4 mol %) in the presence of different electrophiles [Me3SiCl, PriCHO, ButCHO, PhCHO, 4-MeOC6H4CHO, CH3(CH2)6CHO, Et2CO, (CH2)5CO, (c-C3H5)2CO, PhCOMe, 4-MeC6H4COPh, PhCH=NPh, n-C8H7CON(CH2)4] in THF at temperature ranging between −78 and 0°C leads, after hydrolysis
烷基三氟甲磺酸酯的反应1或烯丙基或苄基triflamides 3在不同的亲电子[我的存在下用过量的锂粉末和萘的催化量的(4摩尔%)3的SiCl,镨我CHO,卜吨CHO,苯甲醛, 4-MeOC 6 H 4 CHO,CH 3(CH 2)6 CHO,Et 2 CO,(CH 2)5 CO,(c -C 3 H 5)2 CO,PhCOMe,4-MeC 6 H 4 COPh,PhCH = NPh,n -C在-78至0°C之间的温度下,在THF中的8 H 7 CON(CH 2)4 ]导致水解后生成相应的缩合产物2。当将α,β-不饱和羰基化合物用作亲电子化合物时,取决于所使用的亲电子试剂,发生1,2-(2-环己烯酮)或1,4-加成(肉桂醛或亚苄基丙酮)。
alkyne metathesis will always be the little brother of alkene metathesis, it allows problems to be solved that are currently beyond reach of the more famous sibling. This notion is exemplified by the tulearin macrolides, which could only be selectively forged by ring‐closing alkyne metathesis (RCAM)/trans reduction using the latest generation of alkyne metathesis catalysts.
Lactones are known to react with the reagentgenerated in situ from CCl4 and PPh3 in a Wittig‐type fashion to give gem‐dichloro‐olefin derivatives. Such compounds are now shown to undergo reductive alkylation on treatment with organolithium reagents RLi to furnish acetylene derivatives bearing the substituent R at their termini (R=Me, n‐, sec‐, tert‐alkyl, silyl); the reaction can be catalyzed with
Sodium amalgam mediated desulfonylative reduction of α-functionalized β-ketosulfones
作者:Chieh-Kai Chan、Yi-Hsuan Huang、Meng-Yang Chang
DOI:10.1016/j.tet.2016.07.043
日期:2016.9
Sodiumamalgam mediated desulfonylative reduction of β-ketosulfones in MeOH at rt affords alcohols in good yields via radical desulfonylation of β-ketosulfones and sequential Bouveault-Blanc reduction of the resulting ketones.
5- and 6-Exocyclic Products, <i>cis</i>-2,3,5-Trisubstituted Tetrahydrofurans, and <i>cis</i>-2,3,6-Trisubstituted Tetrahydropyrans via Prins-Type Cyclization
作者:Satish. N. Chavre、Hyunah Choo、Jae Kyun Lee、Ae Nim Pae、Youseung Kim、Yong Seo Cho
DOI:10.1021/jo800967p
日期:2008.10.3
Exocyclic products having cis-2,5 and cis-2,6 substitution were synthesized from terminally substituted alkynyl alcohols with various aldehydes viaPrins-typecyclization in good yields. It is of interest that synthesized 5- and 6-exocyclic vinyl cations generated as a result of Prins-typecyclization could be trapped as a vinyl triflate in CH2Cl2 to give 3-furanylidenes and 3-pyranylidenes. Those