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Synthesis of Cyclopropane‐Containing Phosphorus Compounds by Radical Coupling of Butenylindium with Iodo Phosphorus Compounds
Author(s) -
Kiyokawa Kensuke,
Suzuki Itaru,
Yasuda Makoto,
Baba Akio
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001471
Subject(s) - chemistry , stannane , transmetalation , phosphonate , cyclopropane , photochemistry , bromide , tin , moiety , reagent , organic chemistry , coupling reaction , medicinal chemistry , inorganic chemistry , catalysis , ring (chemistry)
Abstract The radical coupling of α‐ or β‐iodo phosphorus compounds such as iodo phosphonate, iodo phosphane oxide, and iodo phosphonothioate with butenylindium species, prepared by transmetalation between a (cyclopropylmethyl)stannane and InBr 3 , afforded the corresponding cyclopropylmethylated products. The radical reaction was initiated by the radical species generated from butenylindium assisted by a small amount of oxygen. Butenylindium works not only as a cyclopropylmethylating reagent, but also as a radical initiator. For successful coupling, a tin/indium transmetalation was used, where it was important for the tin halide by‐product to be inert to the reaction system. In addition, the transmetalation of a (cyclopropylmethyl)stannane and InBr 3 provided the dibutenylindium bromide as a single product, which smoothly coupled with the unstable phosphonyl radical species from the iodo phosphorus compound. A photochemical method (UV irradiation) was also applied and accelerated the coupling reaction. The cyclopropylmethylated phosphonate produced was a good intermediate in the Horner–Wadsworth–Emmons reaction and gave functionalized olefins bearing the cyclopropane moiety.