1-methylcyclopropyl (MCP) ethers as protecting groups
摘要:
Terminal 1,2- or 1,3-diol acetonides can be converted regioselectively into secondary 1-methylcyclopropyl (MCP) ethers or primary triethylsilyl ethers under mild conditions. MCP ethers are stable to a variety of conditions and can be removed by treatment with NBS or DDQ.
温和的还原剂四甲基铵三乙酰氧基硼氢化物以高非对映选择性将无环 P-羟基酮还原为其相应的反二醇。α-烷基取代不会显着影响这些还原的立体选择性。在所有检查的情况下,都获得了良好到极好的非对映异构体均质二醇的产率。这些还原的机制涉及三乙酰氧基硼氢化物阴离子将乙酸盐与底物醇进行酸促进的配体交换。所得氢化物中间体,大概是烷氧基二乙酰氧基硼氢化物,还原近端 OH 0 OH OH 0 Me,NHB(OAc), Mew Me&OR - OR Me he
Catalytic Enantioselective 1,2-Diboration of 1,3-Dienes: Versatile Reagents for Stereoselective Allylation
作者:Laura T. Kliman、Scott N. Mlynarski、Grace E. Ferris、James P. Morken
DOI:10.1002/anie.201105716
日期:2012.1.9
More with boron: The development of catalyticenantioselective 1,2‐diboration of 1,3‐dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1‐disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized