Gold-Catalyzed Carbene Transfer to Alkynes: Access to 2,4-Disubstituted Furans
作者:Søren Kramer、Troels Skrydstrup
DOI:10.1002/anie.201200307
日期:2012.5.7
example of a gold‐catalyzed intermolecular addition of carbon ylides to terminal alkynes is reported (see scheme; DCE=dichloroethane, Tf=trifluoromethanesulfonyl). Subsequent intramolecular trapping of the generated gold carbene completes a formal [3+2] cycloaddition, which represents a novel synthesis of 2,4‐disubstituted furans.
1] cycloaddition of propargylic carbamates and sulfur ylides was successfully developed. This strategy led to a series of chiral indolines with synthetically flexible alkyne groups in good yields and with high enantio- and diastereoselectivities (up to 99% yield, 98% ee, and >95:5 dr). A possible mechanism and stereoinduction mode with copper-allenylidenes were proposed as the possible dipolar intermediate
Stevens rearrangement of thioethers with arynes: a facile access to multi-substituted β-keto thioethers
作者:Xiao-Bo Xu、Zi-Hua Lin、Yuyin Liu、Jian Guo、Yun He
DOI:10.1039/c7ob00277g
日期:——
An effective method for the synthesis of multi-substituted β-keto thioethers via Stevens rearrangement of simple β-keto thioethers with arynes has been developed. In these reactions, successive C–S/C–H/C–C bonds were formed in one pot under mild and transition-metal free conditions to afford multi-substituted β-keto thioethers in moderate to good yields.
Decomposition of diazoketones in organic sulfides and sulfoxides: Cyclopropane formation from diazoketones via sulfonium ylides
作者:J. Quintana、M. Torres、F. Serratosa
DOI:10.1016/0040-4020(73)80146-2
日期:1973.1
and sulfoxonium ylides as the primary reaction products, the final products isolated depending upon the relative nucleophilicity of the sulfides compared to that of the corresponding ylides, and on the stability of the ylides. The mechanism, scope and limitations of a new method of cyclopropane formation from diazoketones are discussed. Some circumstantial evidence supporting a concerted process for Wolff
Reaction of sulphonium ylides with sulphonyl chlorides
作者:H. Nozaki、M. Takaku、Y. Hayasi、K. Kondô
DOI:10.1016/s0040-4020(01)96869-3
日期:1968.1
In the reaction of carbonyl-stabilized sulphonium ylides with alkane-sulphonyl chlorides, sulphonylation of the ylide carbon usually occurs although olefins VI, an oxathiole derivative VIII and a ketosulphone IX are formed in several cases. These products can be explained by assuming an electrophilic attack of reactive sulphenes on ylides. In contrast to the behaviour of sulphonyl chlorides having