INTRAMOLECULAR CYCLIZATIONS OF CYCLODECENES

许多具有生物学意义的天然产物含有作为其一部分的 结构的一个氢甘菊环，是取代在一个 具有羟基的桥头碳。 例如，肿瘤- 促进佛波醇酯（10）和神经毒性灰蝶毒素。 两步 本文描述了一种用于产生双环[5.3.0]-癸-1-醇的方法 这应该是合成此类结构的通用解决方案。 二乙烯基环己醇的Oxy-Cope重排，随后分子内重排 所得环癸-5-烯酮的烯丙基硅烷缩合导致 所需的氢化甘菊烯醇。 这一顺序的总体结果是环戊烷 环己烷的伴随一碳环膨胀的成环 环，得到氢化甘菊环。 两种不同的变化 该序列应允许制备顺式或反式 将检查氢化甘菊环的环稠合。 其他几 策略，包括涉及跨环自由基环化的策略， 一个是氧稳定的自由基中心，另一个是利用变体 的阴离子加速科普重排，也将进行研究。

Many natural products of biological interest contain as part of their structure a hydroazulene nucleus that is substituted at one of the bridgehead carbons with a hydroxyl group. Examples include the tumor- promoting phorbol esters (10) and the neurotoxic grayanotoxins. A two-step methodology for generating bicyclo[5.3.0]-decan-1-ols is described herein that should be a general solution to the synthesis of such structures. Oxy-Cope rearrangement of a divinylcyclohexanol followed by intramolecular allylsilane condensation of the resultant cyclodec-5-enone leads to the desired hydroazulenol. The overall result of this sequence is cyclopentane annulation with concommitant one-carbon ring expansion of a cyclohexane ring to give the hydroazulene nucleus. Two different variations of this sequence that should allow for the preparation of either the cis or trans ring fusion of the hydroazulene will be examined. Several other strategies, including one that involves transannular radical cyclization of an oxygen-stabilized radical center and another that makes use of a variant of an anion accelerated Cope rearrangement, will also be investigated.