To a stirred mixture of 0.23 g of g of cis-(4-hydroxy-cyclohexyl)-carbamic acid tert-butyl ester, 0.54 g of 1.1′-(azodicarbonyl)-dipiperidine and 20 mL of benzene was added 0.4 g of tri-n-butyl-phosphine and 1.3 g (8 equivalents) of 2,2-difluoro-2-phenyl-ethanol. The mixture was heated to 60° C. overnight, then an additional 0.5 g of 1.1′-(azodicarbonyl)-dipiperidine and 0.4 g of tri-n-butyl-phosphine was added and heating continued for another 24 h. The mixture was cooled, diluted with 25 mL of toluene, filtered and the filter pad washed with 5 mL of toluene. The filtrate was purified by chromatography on silica gel eluting with a gradient of 0%-20% ethyl acetate in hexane gave 0.15 g of product as a resin: 1H NMR (400 MHz, CDCl3) 7.5 (m, 5H), 3.95 (m, 2H), 3.4 (m, 1H), 1.95 (m, 2H), 1.6 (m, 6H), 1.45 (s, 9H).
