A new route to diastereoselective synthesis of (±) trans cognac lactone in five steps is described. The key intermediate methyl 3 formylbutanoate(4) was prepared from methyl crotonate(1) in high yield. Addition o...A new route to diastereoselective synthesis of (±) trans cognac lactone in five steps is described. The key intermediate methyl 3 formylbutanoate(4) was prepared from methyl crotonate(1) in high yield. Addition of n amylmagnesium bromide/cuprous iodide to the formyl of(4), through formation of seven membered ring chelate which involved both carbonyl function groups of (4) and MgX or Cu as a central metal, afforded (±) trans cognac lactone(5) in 52% yield with high diastereoselectivity: ratio of trans to cis isomers was 973 by GC. The procedure had advantages of simplicity, high stereoselectivity of products and mild reaction conditions.展开更多
很时间里,味道是承载一种价值观念的体现,你很难想像一个体味浑浊的人的情趣是值得赏识的——当时间从上个世纪流转到今天,带着浊气与带着香气的男人所体现的是两种截然不同的境界。《红楼梦》里宝哥哥曾说过:女儿是水作的骨肉,男人是...很时间里,味道是承载一种价值观念的体现,你很难想像一个体味浑浊的人的情趣是值得赏识的——当时间从上个世纪流转到今天,带着浊气与带着香气的男人所体现的是两种截然不同的境界。《红楼梦》里宝哥哥曾说过:女儿是水作的骨肉,男人是泥作的骨肉。见了女儿,我便清爽;见了男子,便觉浊臭逼人。宝哥哥可不是浊臭逼人的,胭脂花丛里呆的久了,不免就沾染了香气,只是不知不觉罢了。宝哥哥的年代还是胭脂水粉大行其道,假如有了那个叫EAU DE PARFUM的玩意儿,相信他一定会乐得屁颠儿屁颠儿地给大观园里的姐妹们送去,展开更多
文摘A new route to diastereoselective synthesis of (±) trans cognac lactone in five steps is described. The key intermediate methyl 3 formylbutanoate(4) was prepared from methyl crotonate(1) in high yield. Addition of n amylmagnesium bromide/cuprous iodide to the formyl of(4), through formation of seven membered ring chelate which involved both carbonyl function groups of (4) and MgX or Cu as a central metal, afforded (±) trans cognac lactone(5) in 52% yield with high diastereoselectivity: ratio of trans to cis isomers was 973 by GC. The procedure had advantages of simplicity, high stereoselectivity of products and mild reaction conditions.
文摘很时间里,味道是承载一种价值观念的体现,你很难想像一个体味浑浊的人的情趣是值得赏识的——当时间从上个世纪流转到今天,带着浊气与带着香气的男人所体现的是两种截然不同的境界。《红楼梦》里宝哥哥曾说过:女儿是水作的骨肉,男人是泥作的骨肉。见了女儿,我便清爽;见了男子,便觉浊臭逼人。宝哥哥可不是浊臭逼人的,胭脂花丛里呆的久了,不免就沾染了香气,只是不知不觉罢了。宝哥哥的年代还是胭脂水粉大行其道,假如有了那个叫EAU DE PARFUM的玩意儿,相信他一定会乐得屁颠儿屁颠儿地给大观园里的姐妹们送去,
