A synthetic entry into fused pyran derivatives through carbon transfer reactions of 1,3-oxazinanes and oxazolidines with carbon nucleophiles
作者:Kamaljit Singh、Jasbir Singh、Harjit Singh
DOI:10.1016/0040-4020(96)00879-4
日期:1996.11
of various 2 substituted 1,3-oxazinanes 3 and 1,3-oxazolidines 4 with cyclic carbon nucleophiles viz. 5,5-dimethyl-1,3-cyclohexanedione and 1,3-cyclohexanedione furnish xanthene derivatives, whereas a Knoevenagel reaction proceeds with acyclic nucleophiles. In case of 4b and 4c, a unique synthesis of functionalised α-tetralones has emerged. Reactions of mixtures of cyclic and acyclic carbon nucleophiles
各种2个取代的1,3-恶嗪并3和1,3-恶唑烷4与环状碳亲核试剂的酸催化缩合。5,5-二甲基-1,3-环己二酮和1,3-环己二酮提供了x吨衍生物,而Knoevenagel反应则与无环亲核试剂一起进行。在4b和4c的情况下,出现了功能化的α-四氢萘酮的独特合成。环状和无环碳亲核试剂与3的混合物的反应提供了一些官能化的且部分还原的苯并吡喃衍生物。