Masahito Segi - Cochemist

Chemicals
References

One-pot synthesis of selenoureas and selenocarbamates via selenation of isocyanates with bis(dimethylaluminum) selenide

Co-reporter:Hajime Maeda, Masaru Takashima, Koichi Sakata, Tatsuya Watanabe, Mitsunori Honda, Masahito Segi

Tetrahedron Letters 2011 Volume 52(Issue 3) pp:415-417

Publication Date(Web):19 January 2011

DOI:10.1016/j.tetlet.2010.11.069

Isocyanates were efficiently selenated by the reaction with bis(dimethylaluminum) selenide to give the corresponding isoselenocyanates. One-pot synthesis of unsymmetrical selenoureas and selenocarbamates was achieved in high yields by the subsequent addition of amines and alcoholates to the reaction mixture.

Conjugate addition of vinylic organocuprates generated via transmetalation of phenylseleno-substituted vinylzirconates: Functionalization at the 4-position of enones

Co-reporter:Masahito Segi;Masahiro Suzuki;Kazuki Shintaku ;Hajime Maeda

Heteroatom Chemistry 2011 Volume 22( Issue 3-4) pp:545-552

Publication Date(Web):

DOI:10.1002/hc.20720

Abstract

Hydrozirconation of propargylic selenides (1) or 4-phenylseleno-1-butyne (2) with Cp₂ZrHCl, followed by in situ transmetalation to cuprate (Me₂Cu(CN)Li₂) and addition of enones, led to the formation of 1,4-adducts in good yields. The adducts derived from 1 were subjected to oxidation with H₂O₂ to afford allylic alcohol derivatives via [2,3] sigmatropic rearrangement of allylic selenides. On the other hand, the oxidation of the products derived from 2 gave the corresponding ketones having a conjugated diene moiety at the β-position via selenoxide elimination. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:545–552, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20720