Methanol → trans-(1,1-Diethyl-7-hydroxy-3-methoxy-1,2,3,4-tetrahydronaphthalen-2-yl)-carbamic acid tert-butyl ester

To a slurry of 7,7-diethyl-5-hydroxy-1a,2,7,7a-tetrahydro-1-aza-cyclopropa[b]naphthalene-1-carboxylic acid tert-butyl ester (170.0 g, 535.6 mmol) and methanol (1700 mL) was added pyridinium p-toluenesulfonate (13.4 g, 53.6 mmol) and the reaction mixture was stirred at 40° C. for 4 h. The volume was reduced by rotary evaporation to ˜300 mL resulting in a thick white slurry. The product was isolated by filtration; the filter cake was washed with cold methanol (50 mL) and dried in air for 3 h to yield the title compound (150 g). The filtrate was reduced to ˜50 mL and stirred at 0° C. for 2 h, filtered, and dried to yield additional product (25 g).