Silyl enol ethers are extremely useful nucleophilic intermediates for chemical transformations because they are synthetically versatile substrates for a wide range of C–C bond-forming reactions. Here, we present a new, mild, and solvent-free procedure for the synthesis of silyl enol ethers that employs a catalytic amount of solid-supported base and an equimolar amount of N,O-(bistrimethylsilyl)acetamide
Preparation of Silyl Enol Ethers Using (Bistrimethylsilyl)acetamide in Ionic Liquids
作者:Michael Smietana、Charles Mioskowski
DOI:10.1021/ol015602h
日期:2001.4.1
[reaction: see text]. Ionic liquids have been used for the preparation of silylenolethers from aldehydes and ketones with (bistrimethylsilyl)acetamide (BSA) in good yields.
Treatment of aliphatic carbonylcompounds with trimethylsilyl chloride with Mg turning for Grignard reaction without any pre-treatment in N,N-dimethylformamide at room temperature brought about highly facile, effective and stereoselective coupling to give the corresponding silylenolethers in good yields.
Synthesis of cephalosporin derivatives utilizing the cephem triflate. 1. introduction of 3-position substituents via a cycloaddition-fragmentation route
作者:Han-Young Kang、Sang Hak Lee、Kyung Il Choi、Hun Yeong Koh
DOI:10.1016/0040-4039(96)01714-5
日期:1996.10
An efficient synthetic route for cephalosporinderivatives with various substituents at the 3-position has been developed. It involves cycloaddition with silyl enol ethers or silylketene acetals followedby fragmentation utilizing the 3-cephem triflate1 as a starting material.
Modulators of CRTH2, particularly antagonists of CRTH2, that are useful for treating various disorders, including asthma and respiratory disorders are disclosed. The compounds fall within a genus described by formula I: