Preparation of β-Amino Esters and β-Lactams from Nitriles via Aldimine-Borane Complexes
摘要:
A one-pot synthesis of beta-amino esters has been achieved in 59-75% yield from aromatic and aliphatic nitrites via the condensation of the corresponding non-enolizable and enolizable aldimine-triethylborane complexes, respectively with methyl trimethylsilyl ketene acetals. Grignard-mediated lactamization of the intermediate beta-amino esters provides the corresponding beta-lactams in the same pot in 58-74% overall yield.
Sodium Phenoxide−Phosphine Oxides as Extremely Active Lewis Base Catalysts for the Mukaiyama Aldol Reaction with Ketones
作者:Manabu Hatano、Eri Takagi、Kazuaki Ishihara
DOI:10.1021/ol702052r
日期:2007.10.1
A highly efficient Mukaiyama aldolreaction between ketones and trimethylsilyl enolates catalyzed by sodium phenoxide-phosphine oxides as simple homogeneous Lewis base catalysts (0.5-10 mol %) was developed, which minimized competing retro-aldolreaction. For a variety of aromatic ketones and aldimines, aldol and Mannich-type products with an alpha-quaternary carbon center were obtained in good to
and Michael reactions of silyl enol ethers with carbonyl compounds or other electrophiles (trimethyl orthoformate, dimethyl acetal, and chloromethyl methyl ether), the allylation reaction of allylsilanes with aldehydes, and the Diels–Alder reaction of dienes with α,β-unsaturated aldehydes. A solution of formaldehyde in water is applicable as an electrophile. Also, the aldol-type reaction of ketene silyl
A cationic iridium complex [Ir(cod)2]SbF6 was found to be a new and efficient Lewis acid catalyst for Mukaiyama aldol and Mannich reactions. Aldehydes react smoothly with silyl enol ethers to give β-siloxy ketones in the presence of 0.5 mol % of [Ir(cod)2]SbF6. The reaction of N-alkyl arylaldimines with ketene silyl acetals in the presence of 5 mol % [Ir(cod)2]SbF6/P(OPh)3 gave β-amino esters. After
Reaction of silyl ketene acetals with N-trimethylsilyl imines: a route to N-unsubstituted azetidin-2-ones
作者:Ernest W. Colvin、Daniel G. McGarry
DOI:10.1039/c39850000539
日期:——
Reaction of N-trimethylsilylimines with silylketeneacetals in the presence of ZnI2 and t-butyl alcohol, followed by treatment in situ of the intermediate N-silyl β-aminoesters with MeMgBr, leads to N-unsubstitutedazetidin-2-ones in good yield.
Derivatives of .beta.-aminopropionic acid with a fungicidal activity
申请人:Isagro Ricerca Srl
公开号:US05856311A1
公开(公告)日:1999-01-05
Compounds based on derivatives of .beta.-aminopropionic acid having the general formula (I): ##STR1## The compounds having general formula (I) have a high antifungal activity.