The Journal of Organic Chemistry

Intramolecular [2+ 2] cycloadditions of ketenes. 2. Synthesis of chrysanthenone,. beta.-pinene,. beta.-cis-bergamotene, and. beta.-trans-bergamotene

YS Kulkarni, BB Snider

Index: Kulkarni, Yashwant S.; Snider, Barry B. Journal of Organic Chemistry, 1985 , vol. 50, # 15 p. 2809 - 2810

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Citation Number: 24

Abstract

Diels-Alder reactions of the bis-diene 3 presented two opportunities of diene-dienophile pairing for conversion to an octahydronaphthalene system. In addition, each diene-dienophile pair could interact in four diastereotopic endo- and exo-bridged transition states. Upon heating in o-dichlorobenzene (reflux for 5 min), a remarkably facile cycloaddition was observed solely from the exo-bridged transition state available from conformer 12. Trans-fused ... 15 1 Finally, the synthesis ...