Structure–activity relationship studies of cyclopropenimines as enantioselective Brønsted base catalysts
作者:Jeffrey S. Bandar、Alexandre Barthelme、Alon Y. Mazori、Tristan H. Lambert
DOI:10.1039/c4sc02402h
日期:——
New insights aid in the understanding and design of cyclopropenimine-based asymmetric catalysts.
新的见解有助于理解和设计基于环丙烯亚胺的不对称催化剂。
METHOD FOR PRODUCING SILICA LAYER
申请人:LG CHEM, LTD.
公开号:EP3730223A1
公开(公告)日:2020-10-28
The present application relates to a method for preparing a silica layer. The present application can provide a method capable of easily forming a silica layer, in which pores are formed inside and optical characteristics including a refractive index and the like are appropriately controlled, as a membrane having a silica network as a main component, through a simple process at a low temperature without using expensive equipment.
The present application relates to a glass-like film. The present application can provide a glass-like film capable of solving the disadvantages of the glass material, while having at least one or more advantages of the glass material. Such a glass-like film of the present application can be easily formed through a simple low temperature process without using expensive equipment.
Enantioselective Brønsted Base Catalysis with Chiral Cyclopropenimines
作者:Jeffrey S. Bandar、Tristan H. Lambert
DOI:10.1021/ja3015764
日期:2012.3.28
Cyclopropenimines are shown to be a highly effective new class of enantioselective Bronsted base catalysts. A chiral 2,3-bis(dialkylamino)cyclopropenimine catalyzes the rapid Michael reaction of a glycine imine substrate with high levels of enantioselectivity. A preparative scale reaction to deliver 25 g of product is demonstrated, and a trivial large scale synthesis of the optimal catalyst is shown. In addition, the basicity of a 2,3-bis(dialkylamino)cyclopropenimine is measured for the first time and shown to be approximately equivalent to the P-1-tBu phosphazene base. An X-ray crystal structure of the protonated catalyst is shown along with a proposed mechanistic and stereochemical rationale.