Allenol Ether Intermediates in the Synthesis of 1,7-Dioxaspiro[5.5]undec-4-enes and 1,6-Dioxaspiro[4.5]dec-3-enes
作者:Philip Kocieński、Richard Whitby
DOI:10.1055/s-1991-26640
日期:——
Sequential dialkylation of methoxyallene via the corresponding lithium derivatives gives 1,3-dialkylated methoxyallenes which undergo acid-catalysed ring closure to 1,7-dioxaspiro[5.5]undec-4-enes. Similarly, cyclic allenol ethers (2-vinylidenetetrahydropyrans) generated by rearrangement of 2-alkynyltetrahydropyrans cyclise on treatment with acid to give 1, 6-dioxaspiro[4.5]dec-3-enes.
通过相应的锂衍生物对甲氧基阿伦烯进行序列二烷基化,得到的1,3-二烷基化甲氧基阿伦烯在酸性催化下发生环合反应,生成1,7-二氧杂螺[5.5]十一碳-4-烯。类似地,由2-炔基四氢吡喃重排生成的环状丙三烯醇醚(2-乙烯基四氢吡喃)在酸性处理下发生环合反应,生成1,6-二氧杂螺[4.5]癸-3-烯。