The base-mediated cyclization of selected benzyl alkynyl sulfones with aromatic aldehydes: novel synthetic access to aryl-substituted 5,6-dihydro-1,4-oxathiin S,S-dioxides
摘要:
Based on an unexpected product isolated during the LDA-mediated intramolecular cyclization of a benzyl alkynyl sulfones, a conceptually new cyclization method for the formation of 5,6-dihydro-1,4-oxathiin S,S-dioxides is demonstrated. The reaction affords products with (het)aryl groups at the 5- and 6-positions in 754% yield.[GRAPHICS].
证明了迄今为止未知的LDA诱导的苄基1-炔基砜向1 H -2-苯并噻喃-S,S-二氧化物的转化。苄基碳负离子可通过两种方式进入,被认为是由于芳香族的暂时破坏而环化的。通过ReactIR分析观察到了关键中间体。噻吩衍生物也适合环化,形成7 H-噻吩并[2,3- c ] thiopyran- S,S-二氧化物。