The S (+) sulcatol(1) was prepared in 4 steps. Sodium phenyl sulfinate was reacted with bromoacetone in ethanol to give 1 phenylsulfonyl 2 propanone(2). Alkylation of (2) by 1 chloro 3 methyl 2 butene(3) in the presen...The S (+) sulcatol(1) was prepared in 4 steps. Sodium phenyl sulfinate was reacted with bromoacetone in ethanol to give 1 phenylsulfonyl 2 propanone(2). Alkylation of (2) by 1 chloro 3 methyl 2 butene(3) in the presence of K 2CO 3 through solid liquid PTC in DMF at 40～50 ℃ gave 3 phenylsulfonyl 6 methyl 5 heptene 2 one(4). The sulfone moiety of (4) was removed by Raney Ni reduction under mild conditions and the key intermediate prochiral 6 methyl 5 heptene 2 one(5) was obtained. Sulcatol(1) with optical purity of 94%e.e. was obtained by Baker′s yeast mediated reduction of (5).展开更多
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
文摘The S (+) sulcatol(1) was prepared in 4 steps. Sodium phenyl sulfinate was reacted with bromoacetone in ethanol to give 1 phenylsulfonyl 2 propanone(2). Alkylation of (2) by 1 chloro 3 methyl 2 butene(3) in the presence of K 2CO 3 through solid liquid PTC in DMF at 40～50 ℃ gave 3 phenylsulfonyl 6 methyl 5 heptene 2 one(4). The sulfone moiety of (4) was removed by Raney Ni reduction under mild conditions and the key intermediate prochiral 6 methyl 5 heptene 2 one(5) was obtained. Sulcatol(1) with optical purity of 94%e.e. was obtained by Baker′s yeast mediated reduction of (5).
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.
