A highly enantioselectivecyanosilylation of ketones was developed by using a chiral lithium(I) phosphoryl phenoxide aqua complex as an acid/base cooperative catalyst. The pentacoordinate silicate generated in situ from Me3SiCN/LiCN acts as an extremely reactive cyano reagent. Described is a 30 gram scale reaction and the synthesis of the key precursor to (+)‐13‐hydroxyisocyclocelabenzine.
A new approach to 1-substituted β-carbolines and isoquinolines utilizing tributyl[(Z)-2-ethoxyvinyl]stannane as a C-3,C-4 building block
作者:Alexandra Kamlah、Florian Lirk、Franz Bracher
DOI:10.1016/j.tet.2015.12.049
日期:2016.2
from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substitutedisoquinolines are available in an analogous manner starting
Reduction of Weinreb amides to aldehydes under ambient conditions with magnesium borohydride reagents
作者:Christopher L. Bailey、Jacob W. Clary、Chittreeya Tansakul、Lucas Klabunde、Christopher L. Anderson、Alexander Y. Joh、Alexander T. Lill、Natalie Peer、Rebecca Braslau、Bakthan Singaram
DOI:10.1016/j.tetlet.2014.12.066
日期:2015.1
[H3BNMe2]−, MgAB) is an analogue of the versatile lithium dialkylaminoborohydrides (LAB reagents), prepared by the reaction of dimethylamine-borane with methylmagnesium chloride. MgAB is a partial reducing agent for Weinrebamides under ambient conditions and is complementary to the commonly utilized lithium aluminum hydride (LiAlH4) and diisobutylaluminum hydride (DIBAL) reagents, while exhibiting enhanced
of iminyl radical‐triggered 1,5‐hydrogen atom transfer and (5+2) or (5+1) annulation processes, a series of structurally novel and interesting azepine and spiro‐tetrahydropyridine derivatives have been successfully prepared in moderate to good yields. This method utilizes FeCl2 as the catalyst and readily available oximes as five‐atom units, while showcasing broad substrate scope and good functional