我們的研究是合成出 Brevipolide 。經由七步反應得到中間產物III.8 ，總產?為 18% 。?用Michael-Initiated Ring Closure reactions得到環丙烷並具有部分非鏡像選擇性。醇上接有?同保護基會有?同的選擇性，?如：以 TBS和 MOM保護的?飽和銅得到已 R,R 為主的環丙烷，比?為 6.2 ：1 。另一方面，以縮醛保護的銅得到以S,S 為主的環丙烷，比?為 1 ：2.4 。將MOM保護去掉的化合物 III.9 ，可用 X-ray 繞射?鑑定環丙烷上?體結構。 This study is aimed to achieve the synthesis of Brevipolide. So far, the key intermediate III.8 was prepared in 7 steps with an overall yield of 18%. Michael-Initiated Ring Closure reactions were the key step to provide the cyclopropane moiety with diastereoselectivity. The facial selectivity was different for the substrates with different hydroxyl protecting groups, i.e. the TBS- and MOM-protected alfa,beta-unsaturated ketone gave the major R,R-cyclopropane (dr, 6.2:1), on the other hand, the acetonide-protected ketone provided the S,S-cyclopropane (dr, 1:2.4). The stereo-assignment of the R,R-cyclopropane was confirmed by the X-ray crystallography of the subsequent MOM-deprotected product III.9.
