Total synthesis of carbohydrates. 5. Stereochemistry of the epoxidations of acyclic allylic amides. Applications towards the synthesis of 2,3,6-trideoxy-3-aminohexoses
Diastereoselective Synthesis of 2-Phenylselenenyl-1,3-anti-Diols and 2-Phenylselenenyl-1,3-anti-Azido-Alcohols via Hydroxyand Azido-Selenenylation Reactions
作者:Serena Riela、Carmela Aprile、Michelangelo Gruttadauria、Paolo Meo、Renato Noto
DOI:10.3390/10020383
日期:——
A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
Transition-Metal-Free Allylic Borylation of 1,3-Dienes
作者:Ricardo J. Maza、Elliot Davenport、Núria Miralles、Jorge J. Carbó、Elena Fernández
DOI:10.1021/acs.orglett.9b00531
日期:2019.4.5
This work explains the reactivity of diboron reagents with 1,3-dienes in a transition-metal-free context. The sole addition of Na2CO3 (30 mol %) to bis(pinacolato)diboron in MeOH allows the 1,4-hydroboration of cyclic and noncyclic 1,3-dienes. The electronic influence on the substrate guarantees the conjugated 1,4-hydroboration versus 1,2-diboration. DFT calculations show that the distribution of charge
这项工作解释了在无过渡金属的情况下乙硼试剂与1,3-二烯的反应性。将Na 2 CO 3(30mol%)仅添加至在MeOH中的双(频哪醇)二硼中,可以使环状和非环状的1,3-二烯进行1,4-氢硼化。电子对底物的影响保证了共轭的1,4-氢硼化与1,2-二硼化。DFT计算表明,烯丙基阴离子中间体中的电荷分布决定着1,4-氢硼化的选择性,而二烯试剂中有利的反式构型决定了对烯丙基硼酸E酯的偏爱。
An Efficient Procedure for the 1,3-Transposition of Allylic Alcohols Based on Lithium Naphthalenide Induced Reductive Elimination of Epoxy Mesylates
作者:Hsing-Jang Liu、Jia-Liang Zhu、Yen-Ku Wu
DOI:10.1055/s-2008-1032092
日期:——
An efficient protocol for the 1,3-transposition of allylic alcohols has been developed. The method is based on the pretransformation of allylic alcohols into the corresponding epoxy mesylates, followed by the reductive elimination of the resulting epoxy mesylates by using lithium naphthalenide (LN) as a reducing agent.
A synthetic method for N-protected allylic amines from allyl ethers using chlorosulfonyl isocyanate (CSI) is presented. The reaction of 4-phenylbut-2-enyl methyl ether (1i) with CSI afforded methyl N-(1-benzylallyl)carbamate (2i) and methyl N-(4-phenylbut-2-enyl)carbamate (3i) in a 1:1.1 ratio. On the other hand, 1-benzylallyl methyl ether (1k) afforded the same products in a 4.6:1 ratio. The reactions
Stereoselective preparation of 2-silylated 1,3-diols and the regioselectivity of their Peterson olefination
作者:Jürg Fässler、Anthony Linden、Stefan Bienz
DOI:10.1016/s0040-4020(98)01194-6
日期:1999.2
the stereochemical control of the reaction. The presence of the β-hydroxy functionality, however, also seems to be necessary for a high degree of selectivity. Peterson olefination of 2-silylated 1,3-diols afforded stereoselectively (E)-configured allylic alcohols as the major products. With KH as the base, the reaction proceeds predominattly in a syn-fashion, preferring to eliminate a syn- rather than