Disulfonimide‐Catalyzed Asymmetric Reduction of
<i>N</i>
‐Alkyl Imines
作者:Vijay N. Wakchaure、Philip S. J. Kaib、Markus Leutzsch、Benjamin List
DOI:10.1002/anie.201504052
日期:2015.9.28
A chiral disulfonimide (DSI)‐catalyzedasymmetric reduction of N‐alkyl imines with Hantzsch esters as a hydrogen source in the presence of Boc2O has been developed. The reaction delivers Boc‐protectedN‐alkyl amines with excellent yields and enantioselectivity. The method tolerates a large variety of alkyl amines, thus illustrating potential for a general reductive cross‐coupling of ketones with diverse
A novel cationic [IrH(THF)(P,N)(imine)] [BArF] catalyst containing a P-stereogenic MaxPHOX ligand is described for the direct asymmetrichydrogenation of N-methyl and N-alkyl imines. This is the first catalytic system to attain high enantioselectivity (up to 94% ee) in this type of transformation. The labile tetrahydrofuran ligand allows for effective activation and reactivity, even at low temperatures
A Highly Enantioselective Organocatalytic Method for Reduction of Aromatic
<i>N</i>
‐Alkyl Ketimines
作者:Chao Wang、Xinjun Wu、Li Zhou、Jian Sun
DOI:10.1002/chem.200801479
日期:2008.10.10
PROCESS FOR PREPARING REDUCTANTS OF UNSATURATED ORGANIC COMPOUNDS BY THE USE OF TRICHLOROSILANE AND REDUCING AGENTS
申请人:TOKUYAMA CORPORATION
公开号:EP1086941B1
公开(公告)日:2005-08-17
MULTIFUNCTIONALIZED POLYETHYLENE GLYCOL DERIVATIVE AND PREPARATION METHOD THEREFOR
申请人:XIAMEN SINOPEG BIOTECH CO., LTD.
公开号:US20170312363A1
公开(公告)日:2017-11-02
Disclosed are a multifunctionalized polyethylene glycol derivative and a preparation method therefor. The derivative has an H-shaped structure as represented by formula (1) and comprises one linear core LPEG and four PEG branch chains, where n
1
, n
2
, n
3
, and n
4
respectively are the degrees of polymerization of the branch chains, U
1
and U
2
are trivalent branching groups connecting the core LPEG to two of the PEG branch chains, F
1
and F
2
contain a functional group or a protected form R
01
thereof and may or may not contain a branched group G, correspondingly, the number of R
01
is one or more, F
1
and F
2
are either identical or different, any one linking group in the molecule or any linking group formed with an adjacent heteroatom group can either remain stable or be degraded, and any one PEG segment in the molecule is discretely polydispersed or monodispersed. The multifunctional polyethylene glycol is flexible and diverse in terms of branch structures and the lengths of branching arms, has various parameters and performance indicators that are adjustable and easy to control, and has a broad applicability.