Organosulfur compounds. 16. .alpha.-Phosphoryl sulfoxides. 4. Pummerer rearrangements of .alpha.-phosphoryl sulfoxides and asymmetric induction in the transfer of chirality from sulfur to carbon
Insertion of α-Phosphorylcarbene Moiety into S-S and Se-Se Bonds: Synthesis of Dithio- and Diselenoacetals of Formylphosphonates
作者:M. Mikołajczyk、M. Mikina、P. P. Graczyk、P. Bałczewski
DOI:10.1055/s-1996-4355
日期:1996.10
Reaction between diazomethanephosphonates and disulfides or diselenides catalyzed by boron trifluoride - diethyl ether complex leads to insertion of the (RO)2P(O)-CH(:) moiety into S-S and Se-Se bonds, respectively. The proposed method makes it possible to synthesize 2-phosphoryl-substituted 1,3-diselenanes, not available by other means. The yield depends on the reaction conditions. Stereoselectivity of insertion into cyclic systems is discussed. Reactions catalyzed by rhodium(II) acetate or anhydrous copper(II) sulfate afford the relevant sulfides, (RO)2P(O)-CH2SR. The possible ionic and free radical mechanistic pathways are presented.
A new synthesis of the title compounds via acylation of α-lithio-α-phosphorylalkyl sulfides is described. Two additional approaches to these compounds, although less efficient, involve: (a) sulfenylation of O-silylated dialkyl β-ketophosphonates and (b) the Arbuzov reaction of triethyl phosphite with α-chloro-α-methylthiomethyl phenyl ketone. The keto–enol tautomerism of the title compounds and reactivity
Oxetane synthesis: methyl vinyl sulphides as new traps of excited benzophenone in a stereoselective and regiospecific paterno–Büchi reaction
作者:Trevor H. Morris、Edward H. Smith、Roger Walsh
DOI:10.1039/c39870000964
日期:——
The almost exclusive products in the photochemical addition of benzophenone to methyl vinyl sulphides are the 3-methylthio-oxetanes, formed with selectivity for the trans-4-alkyl-3-methylthio configuration, as shown by an X-ray crystal structure determination and difference nuclear Overhauser effect studies.