102210-06-0Relevant articles and documents
Synthesis of polypropionate subunits from cyclopropanes
Defosseux, Magali,Blanchard, Nicolas,Meyer, Christophe,Cossy, Janine
, p. 7632 - 7653 (2007/10/03)
The oxymercuration-reductive demercuration of several cyclopropanealkanol or their derivatives bearing adjacent stereocenters has been investigated in order to synthesize polypropionate subunits. The crucial importance of the ester protecting group for th
Stereocontrol in organic synthesis using silicon-containing compounds. Studies directed towards the synthesis of ebelactone A
Archibald, Sarah C.,Barden, David J.,Bazin, Jerome F.Y.,Fleming, Ian,Foster, Colin F.,Mandal, Ajay K.,Mandal, Amit K.,Parker, David,Takaki, Ken,Ware, Anne C.,Williams, Anne R.B.,Zwicky, Anna B.
, p. 1051 - 1064 (2007/10/03)
Several approaches to the synthesis of ebelactone A 2 are described, culminating in the synthesis of the benzenesulfonate of 2-epi-ebelactone A 161. All the approaches were based on three fragments A, B and C, originally defined in general terms in Scheme 1, but eventually used as the aldehyde 72, the allenylsilane 3 and the aldehyde 139, respectively. They were joined, first B with C, and then B+C with A. In the main routes to fragments A and C, the relative stereochemistry was controlled by highly stereoselective enolate methylations 66 → 67, 68 → 69, and 135 → 136, in each case anti to an adjacent silyl group, and by a highly stereoselective hydroboration of an allylsilane 137 → 138, also anti to the silyl group. The hydroxyl groups destined to be on C-3 and C-11 were unmasked by silyl-to-hydroxy conversions 69 → 70 and 138 → 139 with retention of configuration. The stereochemistry created in the coupling of fragment B to C was controlled by the stereospecifically anti SE2′ reaction between the enantiomerically enriched allenylsilane 3 and the aldehyde 139. The double bond geometry was controlled by syn stereospecific silylcupration 148 → 151, and preserved by iododesilylation 151 → 152 of the vinylsilane with retention of configuration, and Nozaki-Hiyama-Kishi coupling with the aldehyde 72 gave the whole carbon skeleton 153 of ebelactone A with the correct relative configuration, all of which had been controlled by organosilicon chemistry. In the steps to remove the superfluous allylic hydroxyl, an intermediate allyllithium species 156 abstracted the proton on C-2, and its reprotonation inverted the configuration at that atom. Other routes to the fragments A and C were also explored, both successful and unsuccessful, both silicon-based and conventional, and a number of unexpected side reactions were investigated.
Synthesis of stereotriads by oxymercuration of substituted cyclopropylcarbinols.
Cossy,Blanchard,Meyer
, p. 2567 - 2569 (2007/10/03)
[structure: see text] Cyclopropylcarbinol derivatives bearing an adjacent methyl-substituted stereocenter and a remote beta-hydroxy group protected as a pivalate underwent anchimerically assisted regio- and diastereoselective oxymercurations, affording af
Stereoselective Total Synthesis of (+/-)-Invictolide. An Efficient Preparation of a Trisubstituted δ-Lactone from Aldol Precursors
Pilli, Ronaldo Aloise,Murta, Maria Marcia
, p. 338 - 342 (2007/10/02)
The stereoselective total synthesis of (+/-)-invictolide (1), a component of the queen recognition pheromone of Solenopsis invicta, is described.The TiCl4-mediated addition of silyl ketene thioacetal 8 to (+/-)-3-(benzyloxy)-2-methylpropionaldehyde afford
Diastereoselective Synthesis of 2,3-anti-5-Benzyloxy-2,4-dimethyl-1,3-pentanediols via Cyclic Hydroboration
Yokoyama, Yasushi,Terada, Yuji,Kawashima, Hideyuki
, p. 2563 - 2565 (2007/10/02)
The treatment of (2E,4S)- and (2Z,4S)-1-benzyloxy-5-ethenyloxy-2,4-dimethyl-2-pentene with borane both with and without a catalytic amount of Rh(Ph3P)3Cl gave 2,3-anti-3,4-anti-(2R,3R,4S)- and 2,3-anti-3,4-syn-(2R,3R,4R)-5-benzyloxy-2,4-dimethyl-1,3-penta
LEWIS ACID MEDIATED ALDOL CONDENSATIONS USING THIOESTER SILYL KETENE ACETALS
Gennari, Cesare,Beretta, M. Grazia,Bernardi, Anna,Moro, Giorgio,Scolastico, Carlo,Todeschini, Roberto
, p. 893 - 910 (2007/10/02)
BF3-OEt2 mediated thioester silylketene acetal additions to aldehydes are stereoconvergent and give high anti-syn ratios and good chemical yields.An acyclic transition state model was hypothesized in order to account for the observed selectivity.Theoretic
STEREOSELECTIVE ALDOL REACTIONS USING TiCl4 AS STEREOCHEMICAL TEMPLATE
Gennari, Cesare,Bernardi, Anna,Scolastico,Carlo,Potenza, Donatella
, p. 4129 - 4132 (2007/10/02)
TiCl4 mediated aldol condensations establish multiple contiguous chiral centers in an almost complete enantio- and diastereoselective way.
STEREOSELECTIVE ALDOL CONDENSATIONS VIA ALKENYLOXY DIALKYOXYBORANES: SYNTHETIC APPLICATIONS USING THIOESTERS.
Gennari, Cesare,Bernardi, Anna,Cardini, Silvia,Scolastico, Carlo
, p. 4059 - 4066 (2007/10/02)
A detailed investigation of the enolization of phenyl thiopropionate with ethylenechloroboronate (ECB) and diisopropylethylamine (DPEA) and the subsequent aldol condensations of these enolates was conducted.Alkenyloxy dialkoxyboranes derived from thioesters were found to be stereoconvergent: both Z and E enolates give syn aldol condensation products.The thioester additions to chiral aldehydes were studied.Internal selectivity (syn) was usually very high, while the relative stereoselectivity ranged from poor to good, depending on the specific aldehyde used.The aldol products were transformed to known compounds for correlation.
