Synthesis of intermediate for treprostinil production

A method for synthesizing a compound according to Formula I, comprising:

• (a) contacting an aldehyde represented by Formula C
• with a compound selected from the group consisting of Ra—NH2, RaRbN—(CHR′)x—NHRa and R′—OH in the presence of an organolitium;
• wherein
• x is an integer between 0 and 4 inclusive;
• R an alcohol protecting group or is selected from the group consisting of H, straight or branched (C1-C6)alkyl, (C6-C14)aryl, and (C6-C14)aryl(C1-C6)alkylene-;
• and
• Ra, Rb and Rc are each independently selected from the group consisting of H, straight or branched (C1-C6)alkyl, (C3-C6)cycloalkyl, (C3-C14)aryl(C1-C6)alkylene- and (C3-C6)cycloalkyl(C1-C6)alkylene-;
• (b) contacting the product from step (a) with an organolithium to form an ortho-lithiated product, and then contacting the ortho-lithiated product with copper cyanide to form a cuprate;
• (c) contacting the cuprate from step (b) with an allyl halide selected from the group consisting of allyl chloride, allyl bromide and allyl iodide;
• and
• (d) hydrolyzing the product of step (c) to give the Formula I compound.