105881-89-8Relevant articles and documents
Synthesis of 1,4-Dicarbonyl Compounds from Silyl Enol Ethers and Bromocarbonyls, Catalyzed by an Organic Dye under Visible-Light Irradiation with Perfect Selectivity for the Halide Moiety over the Carbonyl Group
Esumi, Naoto,Suzuki, Kensuke,Nishimoto, Yoshihiro,Yasuda, Makoto
supporting information, p. 5704 - 5707 (2016/11/17)
We report the visible-light-induced radical coupling reaction of silyl enol ethers with α-bromocarbonyl compounds to give 1,4-dicarbonyls. The reaction was effectively accelerated using an inexpensive organic dye (eosin Y) as a photoredox catalyst. 1,4-Dicarbonyl compounds alone were afforded, without the generation of carbonyl adducts of the α-halocarbonyls, which are usually generated in the presence of fluoride anions or Lewis acids. A variety of silyl enol ethers, α-bromoketones, α-bromoesters, and α-bromoamides were applied to this system to produce the coupling compounds.
Facile synthesis of silyl enol ethers by Mg-promoted coupling of aliphatic carbonyl compounds with trimethylsilyl chloride
Ishino, Yoshio,Kita, Yoshio,Maekawa, Hirofumi,Ohno, Toshinobu,Yamasaki, Yasuhiro,Miyata, Toshiyuki,Nishiguchi, Ikuzo
, p. 1349 - 1352 (2007/10/03)
Treatment of aliphatic carbonyl compounds with trimethylsilyl chloride with Mg turning for Grignard reaction without any pre-treatment in N,N- dimethylformamide at room temperature brought about highly facile, effective and stereoselective coupling to give the corresponding silyl enol ethers in good yields.
Regioselective synthesis of substituted (3E)-1,3-dienes from chelated allyl-ironcarbene complexes and potassium enoxyborates
B?hmer, Jutta,Hampel, Frank,Schobert, Rainer
, p. 661 - 667 (2007/10/03)
The addition of potassium enoxyborates to the chelated allyl-ironcarbene complex 1 leads to the corresponding η-(3E)-1,3-diene complexes 2 in fair yields. Complexes 2 can be demetalated with ceric ammonium nitrate (CAN) to give unrearranged (3E)-6-oxo-1.3-dienes 3. Prior to decomplexation, the carbonyl group can be further modified. This is demonstrated by the syntheses of the natural terpene alcohol hotrienol and of a complexed methylene- separated dienyne. Potassium enoxyborates are superior to lithium enolates as they are readily prepared in situ from a variety of aldehydes and ketones which do not form sufficiently stable lithium derivatives. In contrast to lithium enolates, only C- C coupling products derived from the 'kinetic' regioisomers are formed from unsymmetrical aliphatic ketones.
Studies on irreversible inhibition of serine proteases by α- sulfonyloxyketone derivatives
Ohba,Wakayama,Ikeda,Takei
, p. 1127 - 1132 (2007/10/03)
α-Sulfonyloxyketone derivatives were found to be active-site directed irreversible inhibitors of serine proteases.
Acylsilane chemistry. Synthesis of regio- and stereoisomerically defined enol silyl ethers using acylsilanes
Reich, Hans J.,Holtan, Ronald C.,Bolm, Carsten
, p. 5609 - 5617 (2007/10/02)
The preparation of enol silyl ethers using a carbonyl addition-Brook rearrangement-elimination sequence was studied. The key intermediate α-silyl-β-X-alkoxides could be prepared in several different ways, including the addition of organolithium or hydride reagents to α-X-acylsilanes (path a, using RM with R = alkyl, aryl, vinyl, alkynyl, silyl, stannyl, phosphinyl, and cyano), the addition of α-X-lithium reagents to acylsilanes (path b, X = phenylthio, phenylsulfonyl), or the addition of silyllithium reagents to α-X-ketones (path c, X = phenylthio, alkoxy). All of the reactions gave complete regiocontrol of silyl enol ether formation, and many gave excellent (>99%) stereocontrol as well. The selectivity of the carbonyl addition, silyl rearrangement, and elimination was studied. For path a, when the R group of RM was a poor carbanion stabilizing group the elimination of the intermediate α-silyl-β-X-alkoxides was stereospecific, and there was a large difference in rate between erythro and threo (erythro > threo). When R was a carbanion stabilizing group, such as aryl or alkynyl, the elimination process became nonstereospecific in some cases, and only small differences between threo and erythro were observed. Path b was especially effective with α-sulfonyl lithium reagents, and these reactions gave predominantly E enol silyl ethers (4/1 to 20/1). The addition of organolithium reagents to β-X-acylsilanes (the homologue of path a) was also briefly explored as a synthesis of siloxy-cyclopropanes.
CHLOROSILANE-ACCELERATED CONJUGATE ADDITION OF CATALYTIC AND STOICHIOMETRIC ORGANOCOPPER REAGENTS
Matsuzawa, Satoshi,Horiguchi, Yoshiaki,Nakamura, Eiichi,Kuwajima, Isao
, p. 349 - 362 (2007/10/02)
Trialkylsilyl chlorides, particularly in combination with hexamethylphosphoramide or 4-dimethylaminopyridine, dramatically accelerates the conjugate addition of catalytic and stoichiometric organocopper reagents onto enones, enals, and enoates, in which very high degrees of stereo- and chemoselectivities were observed.
REGIO- AND STEREOSELECTIVE PREPARATION OF SILYL ENOL ETHERS BY ALKYLIDENATION OF SILYL ESTERS
Takai, Kazuhiko,Kataoka, Yasutaka,Okazoe, Takashi,Utimoto, Kiitiro
, p. 1065 - 1068 (2007/10/02)
Treatment of trimethylsilyl esters with a reagent for alkylidenation of carbonyl groups derived from 1,1-dibromoalkane, zinc, TiCl4, and TMEDA in THF gives Z-trimethylsilyl enol ethers in a regio- and stereoselective manner.
Silyl Ketone Chemistry. Synthesis of Regio- and Stereoisomerically Pure Enol Silyl Ethers Using α-Phenylthio Silyl Ketones
Reich, Hans J.,Holtan, Ronald C.,Borkowsky, Samuel L.
, p. 312 - 314 (2007/10/02)
The addition of a number of organometallic reagents to α-phenylthio silyl ketones proceeds with good to excellent diastereoselectivity.The products undergo Brook rearrangement and fragmentation to enol silyl ethers with, in most cases, excellent stereoche
