Synthesis of (±)-Hamigeran B, (−)-Hamigeran B, and (±)-1<i>-epi</i>-Hamigeran B:  Use of Bulky Silyl Groups to Protect a Benzylic Carbon−Oxygen Bond from Hydrogenolysis

2004-04-16T00:00:00Z (GMT) by Derrick L. J. Clive Jian Wang
Enone <b>42</b> was converted into diene <b>56</b>, which was then subjected to hydrogenation. Use of the <i>tert</i>-butyldimethylsiloxy groups enforces facial selectivity and protects the C(5) oxygen from hydrogenolysis. The resulting product (<b>55</b>) is easily converted into hamigeran B (<b>1</b>), a marine natural product with powerful activity against herpes and polio viruses. Optically pure enone <b>73</b> was made by use of a Meyers' auxiliary and converted into (−)-hamigeran B with the natural absolute configuration.