反应详情

N-(4'-chlorobenzyl)-2-ethoxymethylene-3-oxobutanamide (1.4 g) and tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedianato)ytterbium (0.26 g) were stirred in toluene (10 ml) whilst 1,1-diethoxyprop-1-ene (4 g) was added dropwise. The mixture was stirred at room temperature for 3 days and evaporated to dryness. The residual gum was triturated with petroleum ether b.p. 60°-80° C. to give a solid which was recrystallised from a mixture of toluene and petroleum ether b.p. 60°-80° C. to give cis-N-(4'-chlorobenzyl)-2,2-diethoxy-3,6-dimethyl-4-ethoxy-3,4-dihydro-2H-pyran-5-carboxamide (0.9 g) m.p. 97°-100° C.

1. additionwas added dropwise
2. customevaporated to dryness
3. customThe residual gum was triturated with petroleum ether b.p. 60°-80° C.
4. customto give a solid which
5. customwas recrystallised from a mixture of toluene and petroleum ether b.p. 60°-80° C.