Method of preparation of an alkyne with an optically active hydroxyl group in the beta or gamma position of a triple bond and intermediates obtained
申请人:Garel Laurent
公开号:US20070004942A1
公开(公告)日:2007-01-04
The present invention relates to a method of preparation of an alkyne with an optically active hydroxyl group in the β or γ position of a triple bond and intermediates obtained. The method of the invention for preparation of an alkyne with an optically active hydroxyl group in the β position of a triple bond is characterized in that it comprises the reaction, in the presence of a Lewis acid:
of a compound of formula (IV):
in which: R is a linear or branched alkyl group having from 1 to 6 carbon atoms. and of a compound of formula (V):
R′—C≡C-M (V)
in which: R′ represents a hydrogen atom, a linear or branched alkyl group having from 1 to 8 carbon atoms, preferably a methyl group or a trialkylsilyl group. M represents a metal, preferably a metal of group (Ia) of the periodic table, preferably lithium. Another object of the invention comprises the production of an alkyne with an optically active hydroxyl group in the γ position of a triple bond by isomerization of an alkyne with an optically active hydroxyl group in the β position previously obtained.
The present invention is directed to a novel method for preparing a synthetic intermediate for treprostinil via a stereoselective alkyne addition reaction. Also described are methods of preparing treprostinil comprising the alkyne addition reaction described herein as well as novel intermediates useful for synthesis prostacyclin derivatives, such as treprostinil.
A new synthesis of treprostinil is described using a plug flow reactor in two of the key steps. First, a Claisen rearrangement reaction is described in scaled flow at multigram amounts. Yields and selectivity of this step are sharply improved compared to those from previous syntheses. Second, the key Pauson-Khandreaction in flow is described under catalytic conditions with 5 mol% of cobalt carbonyl