A series of 9-(hydroxy)alkyl xanthenes 5 was prepared in good yields via: (a) addition of 9-lithioxanthene to functionalized acetaldehydes, or, via a new method, (b) addition of carbanions to xanthene-9-carbaldehyde. A practical and efficient synthesis was found for the latter. Under acidic catalysis, the majority of the addition products underwent Wagner-Meerwein rearrangement to give either the corresponding, 10-substituted dibenz[b,f]oxepin 6 or the xanthenylid-9-ene β-elimination product 7. The first Wagner-Meerwein rearrangement of a homobenzylic cyanohydrin is reported. The dibenz[b,f]oxepins are potential precursors of neuroactive substances. To rationalize product distribution, and probe the scope of the new rearrangement, ab initio quantum mechanical calculations have been carried out on products and transition states in selected cases.

中文翻译：

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9-(α-羟烷基)呫吨的合成和 Wagner-Meerwein 重排为 10-取代的二苯并[b,f]oxepins：范围、限制和从头算计算

通过以下方法以良好的收率制备了一系列 9-(羟基)烷基氧杂蒽 5：(a) 将 9-锂氧杂蒽添加到官能化乙醛中，或者通过一种新方法，(b) 将碳负离子添加到氧杂蒽-9-甲醛中。为后者找到了一种实用且有效的合成方法。在酸性催化下，大多数加成产物经历 Wagner-Meerwein 重排，得到相应的 10-取代二苯并[b,f]oxepin 6 或 xanthenylid-9-ene β-消除产物 7。第一个 Wagner-Meerwein报道了高苄基氰醇的重排。二苯并[b,f]oxepins是神经活性物质的潜在前体。为了使产物分布合理化，并探索新重排的范围，在选定的情况下对产物和过渡态进行了从头算量子力学计算。