6,7-dihydro-5H-spiro[furo[3,2-g]chromene-3,3'-indol]-2'(1'H)-one 、 5,6-dihydrospiro[benzo[1,2-b:5,4-b']difuran-3,3'-indol]-2'(1'H)-one 、
(R)-(tetrahydrofuran-2-yl)methyl 4-methylbenzenesulfonate 、
2-(bromomethyl)tetrahydro-2H-pyran 以1′-[(2R)-tetrahydrofuran-2-ylmethyl]-6,7-dihydro-5H-spiro[furo[3,2-g]chromene-3,3′-indol]-2′(1′H)-one was obtained (57%) as an off-white solid的产率得到1'-[(2R)-tetrahydrofuran-2-ylmethyl]-6,7-dihydro-5H-spiro[furo[3,2-g]chromene-3,3'-indol]-2'(1'H)-one