Simmons-Smith reaction Sodium borohydride

Chemo- and stereoselective reduction of (56) to (55) is achieved In highest yield by sodium borohydride in ethanol. The isolated ketone is reduced more rapidly than the enone and (55) is the equatorial alcohol. Protection moves the double bond out of conjugation and even the distant OH group in (54) successfully controls the stereochemistry of the Simmons-Smith reaction. No cyclopropanation occurred unless the OH group was there. Synthesis ... [Pg.371]

Simmons-Smith cyclopropanation, 456 Simmons-Smith reaction, 455 six-centered transition state, 264 Smiles-type rearrangement, 7 SOCI2, 19, 159 sodium azide, 365, 375 sodium borohydride, 416 sodium hexamethyldisilazide, 290 sodium hydride, 372, 375. 383 sodium in liquid ammonia, 440 sodium iodide, 379 sodium phenylselenide, 458 sodium trifluoroethoxide, 447 solid phase synthesis, 25 Sonogashira conditions, 409 Sonogashira coupling, 411 spartadienedione, 144 spontaneous csdodimerization, 23 S-shaped and C-shaped diastereomers, 83 stainless steel reactor, 283... [Pg.474]