Enantioselective Allylation of <i>β</i><i>,</i><i>γ</i>-Unsaturated Aldehydes Generated via Lewis Acid Induced Rearrangement of 2-Vinyloxiranes
作者:Mark Lautens、Matthew L. Maddess、Effiette L. O. Sauer、Stéphane G. Ouellet
DOI:10.1021/ol016946a
日期:2002.1.1
[reaction: see text] 2-Vinyloxiranes have been found to be excellent surrogates to beta,gamma-unsaturated aldehydes. These valuable electrophiles, generated in situ by treatment of a 2-vinyloxirane with a catalytic amount of Sc(OTf)(3), are effectively trapped by the chiral allylating agents based on alpha-pinene, affording bishomoallylic alcohols in high yield and excellent selectivity.
Contemporaneous Dual Catalysis: Aldol Products from Non‐Carbonyl Substrates
作者:Barry M. Trost、Jacob S. Tracy
DOI:10.1002/chem.201502973
日期:2015.10.19
carbon–carbon bond‐forming reactions vital to modern organic synthesis. Despite the attention this reaction has received, issues related to chemo‐ and regioselectivity as well as reactivity of readily enolizable electrophiles remain. To help overcome these limitations, a new direct approach toward aldol products that does not rely upon carbonyl substrates is described. This approach employs room‐temperature
Preparation of Homoallylic Homopropargylic Alcohols from 2-Vinyloxiranes
作者:Matthew L. Maddess、Mark Lautens
DOI:10.1021/ol051326l
日期:2005.8.1
beta, gamma-Unsaturated aldehydes generated in situ by treatment of 2-vinyloxiranes with a catalytic amount of Sc(OTf)3 or (BFOEt2)-O-. are effectively trapped by B-allenyl-9-BBN to afford homoallylic homopropargylic alcohols in high yield. An enantioselective version has been demonstrated, and a convenient synthesis of 9-allenyl-9-BBN is described.
Chemo-, regio-, and stereo-selective perfluoroalkylations by a Grignard complex with zirconocene
作者:Motohiro Fujiu、Kazuyuki Negishi、Jie Guang、Paul G. Williard、Shigeki Kuroki、Koichi Mikami
DOI:10.1039/c5dt03039k
日期:——
The synthesis of highly reactive perfluoroalkyl Grignard reagents with early transition metal zirconocene complexes and their new types of highly chemo-, regio-, and stereo-selective perfluoroalkylation reactions are reported with epoxides in particular. The zirconocene complex is advantageous in activating the perfluoroalkyl Grignard species. The zirconocene·Grignard complexes were clarified by DOSY
Enantioselective Allylation and Crotylation of in situ Generated β,γ-Unsaturated Aldehydes
作者:Mark Lautens、J. McCubbin、Matthew Maddess
DOI:10.1055/s-0031-1289565
日期:2011.12
β,γ-Unsaturated aldehydes generated in situ by treatment of 2-vinyloxiranes with a catalytic amount of Sc(OTf)3 are effectively trapped by ring-strained allyl- and crotylsilane reagents to afford bishomoallylic alcohols as single diastereomers in high enantiomeric excess.