- A practical and scaleable total synthesis of the jaborandi alkaloid (+)-pilocarpine
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The total synthesis of (+)-pilocarpine (as its nitrate salt) has been achieved in nine steps and 30% overall yield starting from racemic 2-(2′,2′-dimethoxyethyl)propane-1,3-diol, which was desymmetrised via an enzymatic protocol. A high yielding synthesis of a key α-ethylidene lactone precursor has been developed, which involves the palladium-catalysed decarboxylation/carbonylation of a 1,3-dioxan-2-one for formation of the γ-butyrolactone ring. Subsequent hydrogenation of the α-ethylidene lactone introduces the C(3)-stereochemistry to give a 72:28 mixture of (+)-pilocarpine and (+)-isopilocarpine, which are readily separable via recrystallisation of the (+)-pilocarpine nitrate salt.
- Davies, Stephen G.,Roberts, Paul M.,Stephenson, Peter T.,Storr, Helen R.,Thomson, James E.
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experimental part
p. 8283 - 8296
(2009/12/28)
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