The synthesis of 3-methyl-1,4-dioxacylopentadecan-2-one (12c) and 3-methyl-1,4-dioxacylohexadecan-2-one  (12d), two new musk odorants, is described  starting from methyl 2-bromopropionic acid (6b)  and allylic alcohol, respectively. The key step of the synthesis  is the ring-closing olefin metathesis (RCM) to the unsaturated 1,4-dioxamacrolides.  Insight into the structure-odor relationship (SOR) is provided  by the synthesis of ten related unsubstituted or methyl substituted  oxamacrolides. Finally, a four step enantioselective synthesis of  both (3R)-(+)- and (3S)-(-)-3-methyl-1,4-dioxacyclopentadecan-2-one  as well as (3R)-(+)- and (3S)-(-)-3-methyl-1,4-dioxacyclohexadecan-2-one  reveals that mainly the (3R)-(+)  enantiomers are responsible for the powerful musky odor characteristic.  Their synthesis starts from ethyl (2S)-2-hydroxypropanoate  (14) or isobutyl (2R)-2-hydroxypropanoate (15) which were treated under acidic conditions  with allyl trichloroacetimidate (16), followed  by titanate mediated transesterification, ring-closing olefin metathesis  and hydrogenation.
                                    本文介绍了分别从 
2-溴丙酸甲酯(6b)和烯丙基醇开始,合成 3-甲基-1,4-二氧杂
环戊烷-2-酮(12c)和 3-甲基-1,4-二氧杂
环十六烷-2-酮(12d)这两种新型
麝香气味剂。合成的关键步骤是通过闭环烯烃偏析(RCM)生成不饱和的 1,4-二氧杂
环戊烷。  通过合成十种相关的未取代或甲基取代的氧杂二茂酰胺,深入了解了结构-气味关系(SOR)。最后,对 (3R)-(+)- 和 (3S)-(-)-3- 甲基-1,4-二氧杂
环十五烷-2-酮以及 (3R)-(+)- 和 (3S)-(-)-3- 甲基-1,4-二氧杂
环十六烷-2-酮进行了四步对映体选择性合成,结果表明主要是 (3R)-(+) 对映异构体产生了强烈的
麝香气味特征。  它们的合成始于(2S)-2-羟基
丙酸乙酯(14)或(2R)-2-羟基
丙酸异丁酯(15),在酸性条件下用三
氯乙酰亚
氨烯丙基酯(16)处理,然后进行
钛酸酯介导的酯交换反应、闭环烯烃偏聚反应和氢化反应。