Alkynoic add

Toste and coworkers reported the first asymmetric intramolecular hydrocarboxylation of an allene by combining a chiral ligand with a chiral counterion on a Au(I) catalyst (Scheme 2.27). Chiral ion pair formation was crucial to the high selectivity [69[. In another account, a related carboxyallene species was proposed to be an intermediate in a Pd-catalyzed cyclization of alkynoic adds [70]. 

Ogata K, Sasano D, Yokoi T, Isozaki K, Seike H, Takaya H, Nakamura M (2012) Pd-complex-bound amino add-based supramolecular gel catalyst for intramolecular addition-cyclization of alkynoic adds in water Chem Lett 41 498-5(X). doi 10.1246/cl.2012.498 Isozaki K, Haga Y, Ogata K, Naota T, Takaya H (2013) Meted array fabrication based on Ultrasound-induced self-assembly of metalated dipeptides. Dalton Trans doi 0.1039/ C3DT51696B... 

A full report has been published on the preparation and synthetic applications of the acetylenic dianions (35) of note here is their use in the preparation of allene-l,3-dicarboxylic acids (36). Kolbe co-electrolysis of 5-alkynoic adds, RC=C(CH2)3C02H, with half-esters of diadds Me02C(CH2) C02H followed by saponification gives the coupled product (37) in 45—50% yield. Alternative conditions have been reported for the preparation of oi-acetylenic acids from o>-iodoacids (esp. from fatty acids) using the lithium acetylide-ethylenediamine complex in HMPA. ... 

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