173673-00-2Relevant articles and documents
Asymmetric synthesis of homoallylic amines and functionalized pyrrolidines via direct amino-crotylation of in situ generated imines
Schaus, Jennifer V,Jain, Nareshkumar,Panek, James S
, p. 10263 - 10274 (2007/10/03)
The asymmetric synthesis of functionalized homoallylic amines and silyl functionalized pyrrolidines through the Lewis acid promoted condensation of chiral (E)-crotylsilanes with sulfonyl imines and in situ generated N-acyl imines is described. We had anticipated that this bond construction could be used in the asymmetric synthesis of the N-terminal amino acid subunit of the nikkomycins. Aryl sulfonyl imines condense with chiral silane reagents in the presence of BF3·OEt2 to form homoallylic arylsulfonyl amines with useful levels of syn selectivity. For cases involving aryl N-acyl imines we have learned that the temperature controls the course of the reaction. For instance, at temperatures of -78°,C or below the major product is the pyrrolidine, while at higher temperatures (-30 to -20°C) the homoallylic amine is produced. For the cases studied, the [3+2]-annulation is limited to aryl imine derivatives, as alkyl- and branched- imines failed to produce the pyrrolidine derivatives: higher reaction temperatures promote the conversion of the annulation product to the homoallylic amines. In double stereodifferentiating reactions with in situ generated imines, good levels of selectivity were achieved in the formation of secondary amines beating syn-anti and syn-syn stereochemical triads. (C) 2000 Elsevier Science Ltd.
An efficient procedure for the preparation of chiral β-substituted (E)-crotylsilanes: Application of a rhodium(II) catalyzed silylformylation of terminal alkynes
Jain,Jain, Nareshkumar F.,Cirillo,Cirillo, Pier F.,Schaus,Schaus, Jennifer V.,Panek,Panek, James S.
, p. 8723 - 8726 (2007/10/02)
Functionalized β-substituted (E)-crotylsilanes (R)-7 and (S)-8, bearing an alkyl or aryl group adjacent to the stereogenic C-Si center have been synthesized in an efficient four-step procedure initiated with a regio- and stereoselective silylformylation o
