Chiral Ca-catalyzed asymmetric additionreactions of 3-substituted oxindoles with N-Boc-imines afford 3-tetrasubstituted oxindole derivativesbearing adjacent quaternary and tertiary chiralcenters, which are key structures for biological activities. Ubiquitous and nontoxic Ca catalysts (1–10 mol %) work well in this reaction, and high yields (up to 99%) and selectivities (up to >99% ee) of the products
Cinchonidinium acetate as a convenient catalyst for the asymmetric synthesis of cis-stilbenediamines
作者:Ryan R. Walvoord、Marisa C. Kozlowski
DOI:10.1016/j.tetlet.2014.12.105
日期:2015.6
Inexpensive and readily available cinchonidinium acetate is an effective catalyst for the syn-selective aza-Henry reaction of arylnitromethanes and aryl imines. The resulting masked cis-stilbenediamine products are produced in excellent diastereoselectivity and good enantioselectivity, and enantiopure material can be achieved via recrystallization. The features of the cinchona catalyst needed for selectivity
Asymmetric additions of thioglycolates and N-Boc aldimines catalyzed by a bifunctional tertiary-amine squaramide
作者:Bo-Xu Feng、Bin Wang、Xin Li
DOI:10.1039/c6ob01645f
日期:——
A highly enantioselective asymmetricaddition reaction of thioglycolates and N-Boc aldimines was promoted by a bifunctional tertiary-amine squaramide catalyst. As a result, a number of chiral N,S-acetal derivatives were efficiently synthesized with good enantioselectivities.
Chiral Calcium Iodide for Asymmetric Mannich-type Reactions of Malonates with Imines Providing β-Aminocarbonyl Compounds
作者:Tetsu Tsubogo、Shota Shimizu、Shū Kobayashi
DOI:10.1002/asia.201300102
日期:2013.5
catalytic asymmetric Mannich‐type reactions of malonates with both N‐Boc‐protected aromatic and aliphatic imines, and resulted in moderate to high yields with high enantioselectivities. To the best of our knowledge, this is the first example of highly enantioselective metal‐catalyzed asymmetric Mannich‐type reactions of malonates with N‐Boc‐protected aliphatic imines. The Mannich adduct was successfully
Organocatalytic Asymmetric Mannich Reaction of Dihydro-3-carboalkoxy-2-quinolones with Preformed<i>N</i>-Boc Imines
作者:Soumendranath Mukhopadhyay、Subhas Chandra Pan
DOI:10.1002/ejoc.201900156
日期:2019.4.24
An organocatalytic enantioselective Mannichreaction between dihydro‐3‐carboalkoxy‐2‐quinolones and preformed N‐Boc imines has been developed. Quinine derived thiourea catalyst was found to be effective to provide the desired products in good yields and with good enantioselectivities.