87640-84-4Relevant academic research and scientific papers
(E)-1-(Phenylsulfonyl)-4-(trimethylsilyl)-1-butene: An Advantageous Synthetic Equivalent for the 1-(1,3-Butadienyl) Anion and the 1,1-(1,3-Butadienyl) Dianion
Meagher, Timothy P.,Shechter, Harold
, p. 4193 - 4198 (2007/10/03)
The (E)-1-(arylsulfonyl)-4-(trimethylsilyl)-1-butenes 9, 25, and 26 are prepared by CuCl2-promoted and by photolytic additions of their precursor 1-arylsulfonyl chlorides and bromides to 4-(trimethylsilyl)-1-butene (14) and then dehydrohalogenation of the resulting 1-(arylsulfonyl)-2-halo-4-(trimethylsilyl)butanes 15a, 15b, 23a, and 23b with KOH, LDA, or n-BuLi. Silylbutene 14 is obtained from reaction of [(trimethylsilyl)methyl]magnesium chloride (16, X = Cl) and allyl bromide (17) and better by protiodesilylations of (E)- and (Z)-1,4-bis(trimethylsilyl)-2-butenes (20) with sulfuric or trifluoroacetic acids. (Arylsulfonyl)(trimethylsilyl)-1-butenes 9, 25, and 26 are converted efficiently by LDA or n-BuLi at -78°C to 1-(arylsulfonyl)-1-lithio-4-(trimethylsilyl)-1-butenes 10, 27a, and 27b, respectively. Reactions of 27a and 27b with deuterium oxide yield (E)-1-(4-chlorophenylsulfonyl)-1-deuterio-4-(trimethylsilyl)-1-butene (28a, 83%) and (E)-1-deuterio-1-(4-methylphenylsulfonyl)-4-(trimethylsilyl)-1-butene (28b, 89%), respectively. 1-Lithio derivatives 10, 27a, and 27b undergo benzylations by benzyl bromide in THF/HMPA with retention of the positions of their olefinic double bonds to give the (E)-2-(arylsulfonyl)-1-phenyl-5-(trimethylsilyl)-2-pentenes 29a, 29b, and 29c, respectively, in 84-90% yields. Of particular interest is that 29a-c are isomerized to their corresponding 2-(arylsulfonyl)-1-phenyl-5-(trimethylsilyl)-3-pentenes 30a-c, respectively, which then undergo conjugative eliminations of their arylsulfonyl and their trimethylsilyl groups to give (E)-5-phenyl-1,3-pentadiene (33) in 56-63% yields upon reactions with TBAF in THF at 25°C. Further, 27b reacts with 1,3-dichloropropane to form 1-chloro-4-(4-methylphenylsulfonyl)-7-(trimethylsilyl)-4-heptene (35) which is cyclized by n-BuLi to 1-(4-methylphenylsulfonyl)-1-(3-(trimethylsilyl)-1-propenyl)cyclobutane (37, 67%). Elimination of 37 by TBAF then gives allylenecyclobutane (34, n = 3, 84%) simply. This study thus reveals that 9, 25, and 26 have outstanding potential as 1-(1,3-butadienyl) anion (7) and 1,1-(1,3-butadienyl) dianion (8) synthons.
Regiocontrolled Synthesis of Mono-, Di, and Trisubstituted Cyclohexenones by Cycloaddition of Vinyl Sulfones to 1-Methoxy-3--1,3-butadienes. Conversion of Alkenes into Effective Dienophilic Reagents
Kinney, William A.,Crouse, Gary D.,Paquette, Leo A.
, p. 4986 - 5000 (2007/10/02)
Cycloaddition of phenyl vinyl sulfone to Danishefky's diene followed by direct ketalization provided 7, a synthon for the 4-(2-cyclohexenyl) anion.Thus, 7 readily undergoes regiospecific γ-alkylation.Ensuing reductive desulfonylation and hydrolysis provides 2-(and 3-)-cyclohexenones efficiently.Zingiberenol, a monocyclic sesquiterpene, was prepared by means of this methodology.Terminal alkenes and cyclic olefins enter into comparable regiocontrolled Diels-Alder addition if they are first subjected to selenosulfonation and oxidation to the vinyl sulfone.Removal of the phenylsulfonyl substituent after condensation provides the adducts which are formally derived from alkylation of the hypothetical C5 anion of 2-cyclohexenone.The scheme can be expanded to include γ-alkylation prior to desulfonylation.By this means, one is able to prepare 4,5-disubstituted 2-(and 3-)cyclohexenones where the nature of the pendant side chains can be widely varied.
A VINYL SULFONE-MEDIATED DIELS-ALDER APPROACH TO THE FULLY REGIOCONTROLLED ELABORATION OF 4,5-DISUBSTITUTED 2- AND 3-CYCLOHEXENONES
Paquette, Leo A.,Kinney, William A.
, p. 5127 - 5130 (2007/10/02)
Reported here is a scheme which enables one to prepare independently 4,5-disubstituted 2- or 3-cyclohexenones where the nature of the pendant sidechains can be widely varied.
