Naphthopyrans and their C4 Alcohols by Cyclization of Substituted Naphthalenes using Potassium t-Butoxide in Dimethylformamide. Generality and Stereochemical, including Conformational, Effects
作者:Robin G. F. Giles、Ivan R. Green、Wendell P. Swigelaar、C. Peter Taylor
DOI:10.1071/ch07301
日期:——
methoxy groups in the substrate by an ethyl substituent and subjecting these to cyclization reaction conditions identical to those originally reported. For shorter reaction times with potassium tert-butoxide in dimethylformamide under nitrogen, the derived 1-ethyl-, 4-ethyl-, and 1,4-diethylnaphthalenes all cyclize to the trans-1,3-dimethyl compounds, whereas longer times yield increasing proportions of
2-烯丙基-3-(1'-羟乙基)-1,4-二甲氧基萘1的高产立体选择性环化得到反式3,4-二氢-5,10-二甲氧基-1,3-的一般性二甲基萘并[2,3-c]吡喃 2 通过用乙基取代基取代底物中的每个甲氧基并将它们置于与最初报道的相同的环化反应条件下进行研究。对于在氮气下与叔丁醇钾在二甲基甲酰胺中的较短反应时间,衍生的 1-乙基-、4-乙基-和 1,4-二乙基萘全部环化为反式-1,3-二甲基化合物,而较长时间产率增加相应的顺式异构体的比例。在空气中,差向异构 C4 醇 rel-(1R,3R,4S)-3,4-dihydro-5-ethyl-4-hydroxy-10-methoxy-1,3-dimethylnaphtho[2,3-c]pyran 50 和它的 rel-(1R,3R,