Guangxun Li

Enantioselective Organocatalytic Transfer Hydrogenation of 1,2-Dihydroquinoline through Formation of Aza-o-xylylene

A new way of forming the aza-o-xylylene with easily accessible 1,2-dihydroquinolines as precursor has been developed. The presence of an electron-donating group at the proper position of 1,2-dihydroquinoline was crucial for protonation of the alkene through dearomatization with a simple Brønsted acid. The in situ forming reactive intermediate was trapped with Hantzsch ester to afford tetrahydroquinolines in excellent yield and enantioselectivity.

Alkyl Transfer from CC Cleavage

Alkyl substituted Hantzsch esters are rationally used as alkylation reagents to replace the nitro groups of nitro olefins to give excellent yields of trans-olefins. The reaction mechanism is considered to proceed through a free radical mechanism, which is different from the corresponding transfer alkylation of imines.

First way of enantioselective synthesis of moxifloxacin intermediate

A new method of enantioselective synthesis of (S,S)-2,8-diazobicyclo [4.3.0] nonane was found by using (R)-2-amino-2- phenyl-ethanol as chiral induction reagent. The entire synthetic process included 8 steps which were easy to operate with high yield. The purification method was only simple recrystallization or even used directly in the next step without further purification. The total yield was 29%.

Step-Controlled Povarov-Type Reaction with 1,2-Dihydroquinolines as Precursors of Dienophiles: Direct Synthesis of Spirocyclic Bi-tetrahydroquinolines and Functionalized 1,2-Dihydroquinolines

A novel Povarov-type reaction for straightforward synthesis of novel spiro bi-tetrahydroquinolines with readily available 1,2-DHQs (1,2-dihydroquinolines) and aromatic imines was developed. The reaction could be selectively stopped at the first stage under a Brønsted acid catalyst to afford the corresponding functionalized 1,2-DHQs conveniently.

Investigation and Application of Amphoteric α-Amino Aldehyde: An in Situ Generated Species Based on Heyns Rearrangement

In situ generation of the reactive amphoteric α-amino aldehyde with simple α-hydroxy ketones and phenylamine via Heyns rearrangement was proven to be feasible. Metal-free domino reactions based on this reactive intermediate were effectively used to afford important N-heterocycles including polysubstituted pyrroles, indoles, and quinoxalines conveniently. A simple starting material, water as the only byproduct, and diversity of the useful products will make this method greatly attractive for pharmaceutics.

Bio-inspired enantioselective full transamination using readily available cyclodextrin

The mimics of vitamin B6-dependent enzymes that catalyzed an enantioselective full transamination in the pure aqueous phase have been realized for the first time through the establishment of a new “pyridoxal 5′-phosphate (PLP) catalyzed non-covalent cyclodextrin (CD)-keto acid inclusion complexes” system, and various optically active amino acids have been obtained.