Direct, Mild, and General <i>n</i>-Bu<sub>4</sub>NBr-Catalyzed Aldehyde Allylsilylation with Allyl Chlorides
作者:Makeda A. Tekle-Smith、Kevin S. Williamson、Isaac F. Hughes、James L. Leighton
DOI:10.1021/acs.orglett.7b03193
日期:2017.11.3
A direct, mild, and general method for the enantioselective allylsilylation of aldehydes with allyl chlorides is reported. The reactions are effectively catalyzed by 5 mol % of n-Bu4NBr, and this rate acceleration allows the use of complex allyl donors in fragment-coupling reactions and of electron-deficient allyl donors. The results are (1) significant progress toward a “universal” asymmetric aldehyde
Stereoselective Synthesis of Cyclic Guanidines by Directed Diamination of Unactivated Alkenes
作者:Artur K. Mailyan、Kyle Young、Joanna L. Chen、Bradley T. Reid、Armen Zakarian
DOI:10.1021/acs.orglett.6b02778
日期:2016.11.4
method for a directed stereoselective guanidinylation of alkenes is described. The guanidine unit can be delivered as an intact fragment by a hydroxy or carboxy group, usually with a high level of stereocontrol. After the guanidine delivery, the directinggroup can be cleaved under exceptionally mild conditions, typically by alcoholysis in the presence of acetic acid. Broad functionalgroup tolerance
Hydroxyl-Directed Stereoselective Diboration of Alkenes
作者:Thomas P. Blaisdell、Thomas C. Caya、Liang Zhang、Amparo Sanz-Marco、James P. Morken
DOI:10.1021/ja504228p
日期:2014.7.2
An alkoxide-catalyzed directed diboration of alkenyl alcohols is described. This reaction occurs in a stereoselective fashion and is demonstrated with cyclic and acyclichomoallylic and bishomoallylic alcohol substrates. After oxidation, the reaction generates 1,2-diols such that the process represents a method for the stereoselective directed dihydroxylation of alkenes.
Ping-pong polymerization by allylation and hydroformylation for alternating vinyl alcohol–vinyl monomer copolymers
作者:Shingo Ito、Masaki Noguchi、Kyoko Nozaki
DOI:10.1039/c2cc34980a
日期:——
Inspired by the enzymatic ping-pong mechanism, we designed a novel âping-pong polymerizationâ, which employs allylation and hydroformylation in an iterative and alternating manner. Thus, alternating and regioregular vinyl alcoholâvinyl monomer copolymers possessing multiple hydroxy groups in a periodical manner were successfully synthesized.
The successful example of chiral formamides that function as asymmetriccatalysts is described. (S,S)-N,N-Bis(α-methylbenzyl)formamide mediates the enantioselective addition of allyl- and crotyltrichlorosilanes to aliphatic aldehydes with the assistance of hexamethylphosphoramide (HMPA) to afford the corresponding homoallylic alcohols in up to 98% enantiomeric excess.