Novel Reactivity of Main Group Alkynylmetals and Its Application to Organic Synthesis

主族金属的1-炔基有机金属在有机合成中作为高效的亲核试剂被广泛使用。它们与各种亲电试剂反应，一般在碳α到金属原子。为了开发一种构建复杂碳框架的收敛方法，研究了迄今为止尚未探索的β位炔基金属的亲核反应性。研究表明，在分子内反应中，各种炔基金属均在β位反应。带远离基的烷基锌酸盐在β位置进行平滑的外环化，同时配体在锌原子上进行1,2 -迁移，得到1-（环烷基基）烷基锌试剂，该试剂可用于与亲电试剂的后续反应。锂、钠和钾的烷基金属也发生外环化反应生成环烷基烯。本文提出了一种利用炔基金属的外环化和所得到的碳烯的分子内碳氢插入来合成多环化合物的方法。

1-Alkynyl organometallics of main group metals have been frequently used as efficient carbon nucleophiles in organic syntheses. They react with a variety of electrophilic reagents generally at the carbon α to the metal atom. In order to develop a convergent method for the construction of complex carbon frameworks, a hitherto unexplored nucleophilic reactivity of alkynylmetals at the β position is investigated. The study reveals that various alkynylmetals react at the β position especially in intramolecular reactions. Alkynylzincates bearing a remote leaving group undergo smooth exo-cyclization at the β position with simultaneous 1, 2-migration of a ligand on the zinc atom to give 1-(cycloalkylidene) alkylzinc reagents, which can be used in subsequent reactions with electrophiles. Alkynylmetals of lithium, sodium, and potassium also undergo exo-cyclization to give cycloalkylidene carbene. A method for the synthesis of polycyclic compounds is developed utilizing the exo-cyclization of alkynylmetals and intramolecular C-H insertion of the resulting carbenes.