A full account on rhodium‐catalyzed asymmetric, directed hydroboration of functionalized prochiral cyclopropenes affording enantiomerically enriched cyclopropylboronates is reported. The scope and limitations of two alternate directing groups, ester and carboxamide, are evaluated. It was found that hydroboration of esters appeared to be more sensitive to substitution in the aromatic ring of the substrates
Catalytic Enantioselective Hydrostannation of Cyclopropenes
作者:Marina Rubina、Michael Rubin、Vladimir Gevorgyan
DOI:10.1021/ja0496928
日期:2004.3.1
The first examples of catalytic enantioselective hydrostannation of the C=C double bond of cyclopropenes has been demonstrated. This method allows for the efficient synthesis of 2,2-disubstituted cyclopropylstannanes with high degrees of diastereo- and enantioselectivity. The facial selectivity of this reaction is entirely controlled by steric factors. A variety of functional groups at C-3 of the cyclopropenes were tolerated.
Rhodium-Catalyzed Hydroformylation of Cyclopropenes
作者:William M. Sherrill、Michael Rubin
DOI:10.1021/ja805059f
日期:2008.10.15
The first catalytic diastereo- and enantioselective hydroformylation of cyclopropenes was demonstrated. The reaction proceeds efficiently under very mild conditions and low catalyst loadings providing high yields of cyclopropylcarboxaldehydes. This novel methodology represents a convenient, atom-economic approach toward optically active cyclopropylcarboxaldehydes from readily available prochiral cyclopropenes.