Template-directed RCM

One specific case of favorable conformational benefit for a RCM is the template-directed RCM where non-covalent interactions around an appropriate acidic and/or metal template serve to favor productive conformations. This has been found to be useful for linear substrates devoid of intrinsic conformational constraints [19]. RCM of ether 17 in the presence of lithium ions gives the best yield of product 18, in accordance with the preferential binding of Li+ by [12]crown-4, which resembles diene 17 (Scheme 2.7). 

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