Chiral auxiliaries ring-closing metathesis strategy

Davies and co-workers also applied a ring-closing metathesis strategy in their preparation of constrained p-amino acid derivatives. Their work employed a chiral auxiliary, S -(l-phenyl-ethyl)-carbamic acid benzyl ester, to achieve the desired P-amino acid derivatives in a stereoselective fashion. Treatment of diene precursors 46 and 48 with 4 mol % of 3 in refluxing dichloromethane provided the corresponding carbocyclic P-amino acid derivatives 47 and 49 in 85 and 35% yield, respectively, with greater than 95% diastereoselectivity in both cases. The diminished yield in the case of 49 is presumably due to sterics effects. 

Hughes and co-workers applied their ring-closing metathesis strategy using zizane as a chiral auxiliary to the synthesis of enantiopure seven-... 

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