Even though under optimized conditions, cyclization of diene 1 led to rather a clean formation of a diastereomeric mixture ofproducts 1a (d.r.=4:1), the pure major isomer 1a was isolated by column chromatography in only 56% yield. The separation of isomers by column chromatography was problematic and led to a significant loss of the yield, which needed to be solved Scaled-up synthesis. The whole optimized synthetic protocol is shown in Scheme 1. For us, it was important to elaborate on a method that employed only available and cheap starting materials. The synthesis started from propargyl alcohol (2).