A versatile synthesis, including asymmetric synthesis, of bicyclo[n.1.0]alkanes from cyclic ketones via the magnesium carbenoid 1,3-CH insertion as a key reaction
作者:Tsuyoshi Satoh、Shingo Ogata、Daisuke Wakasugi
DOI:10.1016/j.tetlet.2006.07.140
日期:2006.10
1-chlorovinyl p-tolyl sulfoxides, which were synthesized from various cyclic ketones and chloromethyl p-tolyl sulfoxide in three steps, in high yields, with lithium enolate of tert-butyl acetate or its homologues gave the adducts in quantitative yields. The adducts were treated with isopropylmagnesium chloride in ether in dry toluene as the reaction solvent to afford bicyclo[n.1.0]alkanes in high to quantitative
enolate of carboxylic acid tert-butyl esters or N,N-dimethylacetamide gave adducts in high yields. The adducts were treated with ether solution of isopropylmagnesiumchloride in dry toluene to give bicyclo[n.1.0]alkane derivatives having tert-butyl carboxylate or acetamide moiety on the bridgehead carbon in high to quantitative yields via magnesium carbenoid 1,3-CH insertion reaction. The 1,3-CH insertion
Efficient Synthesis of Cyclopropanecarboxylic Acid Esters Starting from the Conjugate Addition of Lithium Ester Enolates to 1-Chlorovinyl p-Tolyl Sulfoxides
cyclopropanecarboxylates was achieved in three steps using 1-chlorovinyl p -tolyl sulfoxides as key materials. The conjugate addition of lithium ester enolates to the sulfoxides gave tert -butyl 4-chloro-4-( p -tolylsulfinyl)butanoates in high yield. The p -tolylsulfinyl group in the resultant adducts was then removed by the sulfoxide–magnesiumexchange reaction with i -PrMgCl at –60 °C. Cyclization of the desulfinylated