- Diboron glycol ester as well as preparation method, intermediate and application thereof
-
The invention discloses diboron glycol ester as well as a preparation method, an intermediate and application thereof. The diboron glycol ester can be used for inducing reductive coupling reaction with imine as a substrate, and the substrate can be obtained by reaction of aldehyde and ammonia and is very easy to obtain and quite low in cost. The product can be separated from a reaction system onlyby acid-base operation without column chromatography purification, and the post-treatment mode is convenient and easy to operate. The yield of the obtained product is high, and protective group operation is not needed. The diboron glycol ester has chirality, the stereoselectivity of the reductive coupling reaction is generally excellent, and 99% ee chiral diamine can be obtained only through simple recrystallization. The diboron glycol ester can be obtained by reacting diol with diboron glycol ester, the diol is convenient to prepare and easy to amplify, the diol can be recycled from a reaction solution through simple acid-base operation, the recovery rate reaches 95%, and the preparation cost is further saved.
- -
-
Paragraph 0130-0135; 0139-0141
(2020/08/02)
-
- Enantioselective Reductive Coupling of Imines Templated by Chiral Diboron
-
We herein report a general, practical, and highly efficient method for asymmetric synthesis of a wide range of chiral vicinal diamines via reductive coupling of imines templated by chiral diboron. The protocol features high enantioselectivity and stereospecificity, mild reaction conditions, simple operating procedures, use of readily available starting materials, and a broad substrate scope. The method signifies the generality of diboron-enabled [3,3]-sigmatropic rearrangement.
- Chen, Dongping,Li, Kaidi,Tang, Wenjun,Xu, Guangqing,Xu, Ronghua,Zhou, Mingkang
-
supporting information
p. 10337 - 10342
(2020/07/04)
-
- Method for preparing intermediate of chiral vicinal diamine
-
The invention discloses a method for preparing an intermediate of chiral vicinal diamine. The method comprises the following steps: adding a compound IV into a solvent, stirring the compound IV and the solvent in an ice water bath, adding an initiator into the obtained reaction system, adding a reducing agent into the reaction system in batches, heating the reaction system to 20-80 DEG C, and stirring the reaction system; and extracting the reaction system after the reaction is completed, drying the obtained organic phase, filtering the dried organic phase, and performing rotary drying to obtain a compound V that is the intermediate. The preparation method of the invention has the advantages of simplicity and mild reaction conditions, and can be widely applied to industrial production.
- -
-
-
- SULPHONYLATED DIPHENYLETHYLENEDIAMINES, METHOD FOR THEIR PREPARATION AND USE IN TRANSFER HYDROGENATION CATALYSIS
-
A diamine of formula (I) is described, in which A is hydrogen or a saturated or unsaturated C1-C20 alkyl group or an aryl group; B is a substituted or unsubstituted C1-C20 alkyl, cycloalkyl, alkaryl, alkaryl or aryl group or an alkylamino group and at least one of X1, X2, Y1, Y2 or Z is a C1-C10 alkyl, cycloalkyl, alkaryl, aralkyl or alkoxy substituting group. The chiral diamine may be used to prepare catalysts suitable for use in transfer hydrogenation reactions.
- -
-
Page/Page column 8
(2008/06/13)
-
- Highly diastereoselective and enantioselective addition of organometallic reagents to a chiral C2-symmetrical bisimine
-
An efficient and straightforward method has been developed for the preparation of enantiomerically enriched C2-symmetrical vicinal diamines via the addition of organometallic reagents to a chiral bisimine, which gives access to a variety of optically pure aromatic and aliphatic C 2-symmetrical vicinal diamines in high yields. The 'Cram-Davis' open transition state model is proposed to rationalize the observed stereoselectivities for the addition of organolithium reagents to the bisimine. Georg Thieme Verlag Stuttgart.
- Sun, Xiaoxia,Wang, Shuangjun,Sun, Shangjin,Zhu, Jin,Deng, Jingen
-
p. 2776 - 2780
(2007/10/03)
-
- Synthesis of Nitrogen-Containing Macrocycles with Reductive Intramolecular Coupling of Aromatic Diimines
-
Reductive intramolecular coupling of aromatic diimines is an effective method for the synthesis of a variety of nitrogen-containing macrocycles. 1,4-Diazacrown ethers 3 were effectively synthesized by intramolecular coupling of bis(imino ethers) 9 promoted by electroreduction (method A) or chemical reduction with zinc powder (method B) in the presence of methanesulfonic acid.In spite of the formation of macrocycles, the yields of 3 were relatively high.This can be explained by the formation of proton-bridged intermediates 14, in which intramolecular hydrogen bonds are formed between hydrogen and oxygen atoms of diiminium salts.Method B was more effective in the formation of 1,4-diaza-12-crown-4 derivatives 3 (n = 1) due to the template effect of Zn(2+).Optically active macrocyclic bislactones 4 were synthesized stereoselectively by reductive intramolecular coupling of bis(imino esters) 20 with zinc powder (method B).The high stereoselectivity is explained by considering proton-bridged intermediate 23.The resultant compounds 4 were transformed to optically active 1,2-diarylethylenediamines 7.Various sizes of macrocyclic bislactams 5 were synthesized by reductive intramolecular coupling of bis(imino amides) 26 with zinc powder (method B).Reduction of 5 gave the corresponding macrocyclic polyamines 6.
- Kise, Naoki,Oike, Hideaki,Okazaki, Eiichi,Yoshimoto, Masami,Shono, Tatsuya
-
p. 3980 - 3992
(2007/10/02)
-
- A novel method for stereoselective synthesis of (1R,2R)-diarylethylenediamines by reductive intramolecular coupling of aromatic diimines
-
Reduction with zinc has been found to be an effective method for selective synthesis of (1R,2R)-diarylethylenediamines from the corresponding chiral aromatic diimines through their intramolecular coupling.
- Shono, Tatsuya,Kise, Naoki,Oike, Hideaki,Yoshimoto, Masami,Okazaki, Eiichi
-
p. 5559 - 5562
(2007/10/02)
-
