7-Hydroxymethyl-6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene. Exceptionally High Anti to Sulfur Diastereoselectivity under Conditions of Johnson Ortho Ester Claisen Rearrangement Favors Cieplak Mode of Diastereoselection
1 Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India, and Department of Chemistry, The University of Calgary, Calgary, Alberta-T2N 1N4, Canada.