Tetrahydrofuran → tert-Butyl (5S,7S)-1-oxo-2-oxaspiro[4.4]non-8-en-7-ylcarbamate

Participants

Reaction Steps

To a solution of the product of Step D (1149 g, 2.875 mol) and THF (5.75 L) was added TBAF (1M in THF, 2.875 L) over ˜1 h. The reaction was stirred for 1 h at rt, and diluted with EtOAc. The organic layer was washed with brine, diluted with heptanes and the organic layer was further washed with water and brine. The organic layer was evaporated, the crystallized product was filtered, and washed with heptanes to provide the product of Step E as a white solid. 1H NMR (400 MHz, CHLOROFORM-d) d=5.86-5.98 (m, 3H), 5.67 (d, J=5.4 Hz, 3H), 5.03-5.20 (m, 2H), 4.76-4.87 (m, 3H), 4.28 (t, J=7.0 Hz, 5H), 2.08-2.31 (m, 8H), 1.99 (d, J=2.4 Hz, 3H), 1.34 (s, 25H).

Provenance & Evidence