The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

The present disclosure belongs to the technical field of organic synthesis and particularly relates to a preparation method for 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate. The 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is a key chiral intermediate for preparation of statin antilipemic agents. In the present disclosure, the 2-((4R,6S)-6-bromomethyl-2-oxo-1,3-dioxane-4-yl)acetate is obtained by bromination and cyclization of 3-((substituted oxycarbonyl)oxy)-5-hexenoate as raw material with hypochlorite and bromide in an organic solvent in the presence of CO.sub.2. The method of the present disclosure has the advantages of readily available raw material, mild reaction conditions, easy operation, low cost, excellent atomic economy and less by-products, and is applicable to industrial production.

Provided herein are nickel(O) catalysts that are stable when exposed to air and can be used to catalyze the formation of a CC, CO, or CN bond.

Provided herein are nickel(O) catalysts that are stable when exposed to air and can be used to catalyze the formation of a CC, CO, or CN bond.

The present invention uses a candesartan cyclic compound as a starting material and performs thereon a three-step reaction of forming tetrazole, hydrolysis and adding a protecting group to directly obtain trityl candesartan without separating an intermediate product via crystallization. The operating process is simple and thus is more applicable to industrial production.

The present invention uses a candesartan cyclic compound as a starting material and performs thereon a three-step reaction of forming tetrazole, hydrolysis and adding a protecting group to directly obtain trityl candesartan without separating an intermediate product via crystallization. The operating process is simple and thus is more applicable to industrial production.

Provided is a method for preparing L-BPA, which includes steps of: reacting N-protected (S)-4-halophenylalanine of Formula I, a boronating agent, Grignard reagent and bis(2-methylaminoethyl)ether to obtain a reaction mixture, wherein the reaction mixture comprises N-protected (S)-4-boronophenylalanine of Formula II and the R.sup.2 group represents a protecting group;

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isolating the N-protected (S)-4-boronophenylalanine from the reaction mixture; and deprotecting the R.sup.2 group of the N-protected (S)-4-boronophenylalanine to obtain L-BPA, wherein the L-BPA has a structure of Formula III.

Provided is a method for preparing L-BPA, which includes steps of: reacting N-protected (S)-4-halophenylalanine of Formula I, a boronating agent, Grignard reagent and bis(2-methylaminoethyl)ether to obtain a reaction mixture, wherein the reaction mixture comprises N-protected (S)-4-boronophenylalanine of Formula II and the R.sup.2 group represents a protecting group;

##STR00001##

isolating the N-protected (S)-4-boronophenylalanine from the reaction mixture; and deprotecting the R.sup.2 group of the N-protected (S)-4-boronophenylalanine to obtain L-BPA, wherein the L-BPA has a structure of Formula III.