A Ru Catalyzed Divergence: Oxidative Cyclization vs Cycloisomerization of Bis-homopropargylic Alcohols
作者:Barry M. Trost、Young Ho Rhee
DOI:10.1021/ja011840w
日期:2002.3.1
electrophilically initiated direct attack of the hydroxyl group on a pi-complex of the alkyne and ruthenium. A catalytic system composed of CpRu[(p-CH(3)O(6)H(4))(3)P](2)Cl and excess (p-CH(3)O-C(6)H(4))(3)P directs the reaction toward the oxidative cyclization to form delta-lactones in good yields. Significantly, a simple switch of catalyst to CpRu[(p-FC(6)H(4))(3)P](2)Cl redirects the reaction to a cycloisomerization
Stereoselective Synthesis of <scp>d</scp>-Desosamine and Related Glycals via Tungsten-Catalyzed Alkynol Cycloisomerization
作者:Mary H. Davidson、Frank E. McDonald
DOI:10.1021/ol049630m
日期:2004.5.1
Stereoselective synthesis of d-desosamine diacetateester (iii, R = Ac) was achieved from the glycal (ii). generated by tungsten carbonyl-catalyzed cycloisomerization of the corresponding amino-alkynol (i). A wide variety of N-substituents (R, R') are compatible with the cycloisomerization, provided that at least one R or R' is an acyl derivative.