198758-05-3Relevant academic research and scientific papers
NHC-Cu(i) catalysed asymmetric conjugate silyl transfer to unsaturated lactones: Application in kinetic resolution
Pace, Vittorio,Rae, James P.,Harb, Hassan Y.,Procter, David J.
supporting information, p. 5150 - 5152 (2013/06/26)
The scope of the asymmetric silyl transfer to unsaturated lactones utilising a C2-symmetric NHC-Cu(i) catalyst has been established and kinetic resolutions mediated by silyl transfer have been used to prepare enantiomerically enriched anti-4,5-disubstituted 5-membered lactones. The method has been exploited in an expedient synthesis of (+)-blastmycinone.
SmI2-mediated radical cyclizations directed by a C-Si bond
Harb, Hassan Y.,Collins, Karl D.,Altur, Jose V. Garcia,Bowker, Sue,Campbell, Leonie,Procter, David J.
supporting information; experimental part, p. 5446 - 5449 (2011/02/24)
The use of a silicon stereocontrol element in cyclobutanol and cyclopentanol-forming cyclizations mediated by SmI2 results in excellent diastereocontrol. The C-Si bond in the products of cyclization provides a versatile handle for further manip
Rhodium(I)-catalyzed enantioselective 1,4-addition of nucleophilic silicon
Walter, Christian,Fr?hlich, Roland,Oestreich, Martin
experimental part, p. 5513 - 5520 (2009/12/09)
A rhodium(I)-catalyzed activation of a silicon-boron linkage, that is, the transmetalation of silicon from boron to rhodium(I) by means of an RhI-OH complex, enables the conjugate transfer of nucleophilic silicon onto α,β-unsaturated acceptors. Pre- or in situ formed cationic rhodium(I)-binap complexes catalyze this novel carbon-silicon bond formation with exceptional enantiocontrol, 92 to >99% ee for cyclic carbonyl and carboxyl compounds as well as >99% ee for acyclic carboxyl compounds.
Total synthesis of (+)-mycotrienol and (+)-mycotrienin I: Application of assymetric crotylsilane bond constructions
Masse, Craig E.,Yang, Michael,Solomon, Jason,Panek, James S.
, p. 4123 - 4134 (2007/10/03)
A highly convergent asymmetric synthesis of the ansamycin antibiotics (+)-myotrienin I (1c) and (+)-mycotrienol (1d) has been achieved through the synthesis and coupling of the C9-C16 subunit 3b and the aromatic subunit 4b, respectively. This article describes the complete details of that work as it illustrates the utility of our developing chiral (E)-crotylsilane bond construction methodology in total synthesis. All four sterogenic centers were introduced using chiral allylsilane bond construction methodology. In the synthesis of subunit 3b, the C12 and C13 stereocenters were installed using an asymmetric crotylsilylation reaction to α-keto dibenzyl acetal 5. The C11 stereocenter was subsequently installed via a chelate-controlled addition of allyltrimethylsilane to establish the anti-1,3-diol system. The C14-C15 trisubstituted double bond was then installed via a reductive opening of α,β-unsaturated lactone 10b. Aromatic subunit 4b was chosen on the basis of its synthon equivalency to the amidobenzoquinone system of (+)-1c and (+)- 1d. Subunit 4b was constructed in a concise six-step sequence which corporates the C3 stereogenic center of the C1-C5 side chain. The C3 sterogenic center was established using a Weinreb amidation of aniline 18 with lactone (+)-16, whose absolute stereochemistry was derived using the crotylsilane methodology. The union of subunit 3b with aromatic subunit 4b was accomplished using a sulfone-based coupling strategy. Coupling product 21 was transformed through a sequence of steps to triene 24. Divergence from this advance intermediate allows access to both natural products. The successful completion of the synthesis included the incorporation of the (E, E, E)-triene unit with simultaneous macrocyclization through a palladium (0)- catalyzed (Stille-type) coupling macrocyclization.
Claisen Rearrangements of Enantiomerically Pure C3-(Acyloxy)-(E)-vinylsilanes
Sparks, Michelle A.,Panek, James S.
, p. 3431 - 3438 (2007/10/02)
The Ireland ester Claisen rearrangement of chiral (R)- and (S)-(acyloxy)-(E)-vinylsilanes gives access to a wide range of α-chiral-β-silyl-(E)-hexenoic acids with useful levels of diastereoselectivity for both the 2,3-syn and 2,3-anti diastereomers as ill
