Highly Diastereoselective Hydrostannylation of Allyl and Homoallyl Alcohols with Dibutyl(trifluoromethanesulfoxy)stannane
作者:Katsukiyo Miura、Di Wang、Akira Hosomi
DOI:10.1021/ja052245n
日期:2005.7.1
Dibutyl(trifluoromethanesulfoxy)stannane (Bu2Sn(OTf)H, 1a) was found to be very valuable for highly diastereoselective homolytic hydrostannylation of allyl and homoallyl alcohols. alpha,beta-Disubstituted allyl alcohols and alpha,gamma-disubstituted homoallyl alcohols were converted into gamma- and delta-stannylated alcohols with high 1,2-syn and 1,3-syn diastereoselectivity, respectively. The origin of the stereochemical outcomes can be rationalized by conformational fixation of the intermediary beta-stannylalkyl radical by coordination of the hydroxy group to the Lewis acidic tin center.
Functionalized Chromans and Isochromans via a Diastereoselective Pd(0)-Catalyzed Carboiodination
作者:David A. Petrone、Hasnain A. Malik、Antonin Clemenceau、Mark Lautens
DOI:10.1021/ol302111y
日期:2012.9.21
A diastereoselective approach to isochromans and chromans via Pd(0)-catalyzed carboiodination is reported. The transformations using this methodology display excellent yields and diastereoselectivities as well as broad functional group compatibility. The selectivity observed in these cyclizations, forming isochroman or chroman targets, is postulated to originate from the minimization of A(1,2) strain and axial axial interactions, respectively. This method has also been used to highlight the concept of reversible oxidative addition to carbon iodine bonds in polyiodinated substrates.