Next, we attempted to obtain a natural product-Yuzu lactone (Z)-11, a camphor & minty-smelling 13-membered macrocycle isolated from the flesh and peel of the Japanese citrus tree Citrus junos Tanaka (Scheme 3A). Interestingly, this Z-configured unsaturated lactone has been previously obtained using an indirect diyne metathesis/semihydrogenation sequence. 86:14. On the other hand, stereoretentive Ru complex, Ru2 (used in 6 mol% loading) in a diluted DCM solution (3 mM) gave 11 in 68% yield and high selectivity (>95% Z). In this context we were pleased to see that only 1 mol% of Ru3 under the reactive distillation conditions (110 °C, PAO-6, 200 mM) led to yuzu lactone 11 in isolated yield of 66% and high Z-selectivity of 99:1 (Scheme 3A). To further explore the scope of the new stereoretentive catalyst, another experiment was conducted in the presence of 1 mol% of Ru3 leading to the isolation of 19-membered macrocyclic ether 12 with satisfactory yield (68%) and similarly high Z-selectivity (≥98:2 Z/E, Scheme 3A).