Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry
作者:Byron K. Peters、Kevin X. Rodriguez、Solomon H. Reisberg、Sebastian B. Beil、David P. Hickey、Yu Kawamata、Michael Collins、Jeremy Starr、Longrui Chen、Sagar Udyavara、Kevin Klunder、Timothy J. Gorey、Scott L. Anderson、Matthew Neurock、Shelley D. Minteer、Phil S. Baran
DOI:10.1126/science.aav5606
日期:2019.2.22
Scaled-up sodium-free Birchreductions The so-called Birchreduction is frequently used by chemists despite its daunting conditions: Pyrophoric sodium is dissolved in pure liquified ammonia to achieve partial reduction of aromatics. Peters et al. surveyed and then optimized small-scale electrochemical alternatives to devise a safer protocol that can work on a larger scale with a broad range of functionally
Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
作者:Alexander Paptchikhine、Kaori Itto、Pher G. Andersson
DOI:10.1039/c0cc05619g
日期:——
A range of 1,2,4-trisubstituted cyclohexadienes obtained from the Birch reaction were hydrogenated asymmetrically to produce synthetically valuable chiral compounds in high enantio- and diastereoselectivity.
A highly convergent total synthesis of the spiroacetal macrolide (+)-milbemycinβ1
作者:Steven V. Ley、Neville J. Anthony、Alan Armstrong、M.Gabriella Brasca、Trafford Clarke、David Culshaw、Christine Greck、Peter Grice、A.Brian Jones、Barry Lygo、Andrew Madin、Richard N. Sheppard、Alexandra M.Z. Slawin、David J. Williams
DOI:10.1016/s0040-4020(01)89182-1
日期:——
A highlyconvergentsynthesis of the macrolide natural product milbemycin β1 is reported. The key features of this synthesis include the introduction of the C11-C15 side chain by selective ring opening of a symmetrical 1,4-pentane bis-epoxide (3) followed by reaction with the anion derived from the 2,3-trans-dimethyl-6-phenylsulphonyl pyran (2) to afford the “northern” C11-C25 fragment (33) of milbemycin
Cyclopentannulation reactions with organoiron reagents. Facile construction of functionalized hydroazulenes
作者:M. Rosenblum、J. C. Watkins
DOI:10.1021/ja00173a020
日期:1990.8
ketohydroazulene cycloadducts derived, in each reaction, from a single tautomeric tropyllium cation. The further reaction of two such cycloadducts with lithium dimethyl cuprate gave tricyclic ketones, through a sequence depicted as involving initial formation of an anionic acyliron complex, followed by migratory insertion and an intramolecular aldolcondensation
SmI2/H2O/amine promoted reductive cleavage of benzyl-heteroatom bonds: optimization and mechanism
作者:Tobias Ankner、Göran Hilmersson
DOI:10.1016/j.tet.2009.10.086
日期:2009.12
SmI2/H2O/pyrrolidine mediated cleavage of benzylic alcohols and benzyl groups was studied and found to be a viable alternative to the Birch reduction yielding the corresponding deoxygenated product in excellent yield. The reaction has been investigated by kinetic methods, and a mechanism involving a pre-complexation of the alcohol to SmI2 followed by an amine mediated electron transfer and subsequent bond cleavage
研究了SmI 2 / H 2 O /吡咯烷介导的苄醇和苄基的裂解,发现它是桦木还原的可行替代方法,可产生高收率的相应脱氧产物。已经通过动力学方法研究了该反应,并且已经提出了一种机制,该机制涉及将醇预先络合至SmI 2,然后进行胺介导的电子转移,然后进行键裂解以及第二电子和质子的转移以产生甲苯产物。 。在较高的水浓度下,该反应受到强烈抑制,表明该反应是通过内球电子从sa(II)转移至苄基而进行的,过量的水阻止了苄醇与alcohol的配位。