Asymmetric Organocatalytic Sequential Reaction of Structurally Complex Cyclic Hemiacetals and Functionalized Nitro-olefins To Synthesize Diverse Heterocycles
作者:Jun-Ping Pei、Ying-Han Chen、Yan-Kai Liu
DOI:10.1021/acs.orglett.8b01386
日期:2018.6.15
Structurally complex cyclic hemiacetals bearing a racemic tetrasubstituted stereocenter have been prepared in a concise manner and were successfully used in an organocatalytic enantioselective sequence to react with functionalized nitro-olefins, providing bicyclic acetal-containing compounds as two separable epimers with excellent stereoselectivity. The reaction showed broad substrate scope, with respect
The carbon–carbondouble bond in conjugated nitro and certain carbonyl compounds was reduced smoothly and selectively by Hantzsch ester (HEH), an NAD(P)H model, in the presence of a small amount of acetic acid.
The present invention provides compounds of Formula (I), or a pharmaceutically acceptable salt thereof, where R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, A and n are as defined herein. A deuteriated derivative of the compound of Formula (I) is also provided.
O<sub>2</sub>-Mediated Oxidation of Aminoboranes through 1,2-N Migration
作者:Marian Rauser、Daniel P. Warzecha、Meike Niggemann
DOI:10.1002/anie.201803168
日期:2018.5.14
In analogy to the classical reaction of C−B bonds with peroxides, the first oxidative functionalization of aminoboranes through a 1,2‐N migration was realized. Readily available aliphaticnitrocompounds are thereby transformed into N‐ and O‐functionalized hydroxylamines in a single synthetic operation. Addition of hazardous peroxides is avoided. Instead, the insertion of O2, as the terminal oxidant
direct reductive N‐functionalization of aliphatic nitro compounds is presented. The nitro group is partially reduced to a nitrenoid, with a mild and readily available combination of B2pin2 and zinc organyls. Thereby, the formation of an unstable nitroso intermediate is avoided, which has so far severely limited reductive transformations of aliphatic nitro compounds. The reaction is concluded by an electrophilic