Fig. 6: Mechanistic experiments.

a, NaHMDS/HBpin = 1/2. b, NaHMDS/HBpin = 1/2.8. c, NaHMDS/HBpin = 1/3. d, Sodium alkoxide of 1 was added to freshly prepared [HMDS-Bpin]. e, Sodium alkoxide of 1 was added to a mixture of NaHMDS and HBpin (1:2). f, Standard condition after 6 h.