Regioselective synthesis of 1,7-dioxaspiro[4.4]nonanes from a trimethylenemethane dianion synthon
作者:Francisco Alonso、Bruno Dacunha、Jaisiel Meléndez、Miguel Yus
DOI:10.1016/j.tet.2004.10.101
日期:2005.3
2-Chloromethyl-3-(2-methoxyethoxy)prop-1-ene behaves as a versatile trimethylenemethane dianion synthon, precursor of a variety of methylidenic diols obtained by DTBB-catalysed lithiation in the presence of a carbonyl compound (E1=R1R2CO) in THF at −78 to 0 °C, followed by the addition of an epoxide [E2=R3R4C(O)CHR5] at 0 to 20 °C and final hydrolysis. These diols undergo double intramolecular iodoetherification
2-氯甲基-3-(2-甲氧基乙氧基)丙-1-烯的行为是多用途的三亚甲基二价阴离子合成子,它是在羰基化合物存在下通过DTBB催化锂化获得的各种亚甲基二醇的前体(E 1 = R 1 R 2 CO)在-78至0°C下的THF中,然后加入环氧化物[E 2 = R 3 R 4 C(O)CHR 5在0至20℃下进行最终水解。这些二醇在碘和氧化银(I)的存在下于THF或二氧六环-水中进行双分子碘化醚化反应,生成相应的1,7-二氧杂螺[4.4]壬烷,可以很容易地氧化成各种1,7 -dioxaspiro [4.4] nonan-6-ones。这些骨骼存在于多种天然产物中。