AgNTf<sub>2</sub>-Mediated Allylation with Allylsilanes at C3<i>a</i>-Position of Hexahydropyrroloindoles: Application to Total Syntheses of Amauromine Alkaloids
various allyl groups including the reverse prenyl group. The utility of this reaction is demonstrated by total synthesis of amauromine alkaloids. Stepwise bromocyclizations of the bis-indolylmethyl diketopiperazine derivative and subsequent double reverse prenylation furnished (+)-novoamauromine and (−)-epiamauromine.
Kinetics of the reactions of allylsilanes, allylgermanes, and allylstannanes with carbenium ions
作者:Gisela Hagen、Herbert Mayr
DOI:10.1021/ja00013a035
日期:1991.6
isobutene/2k). A close analogy between the reactions of alkenes and allylelement compounds with carbeniumions is manifested, and the different reaction series are connected by well-behaved linear free energy relationships. The relative reactivities of terminal alkenes and allylelement compounds are almost independent of the electrophilicities of the reference carbeniumions (constant selectivity relationship)
Irradiation of an acetonitrile solution containing 2,3-dicyano-5,6-diphenylpyrazine with allylic silanes, benzylsilane, and ketene silyl acetal gave the mono-substituted products in excellent yields. This reaction is useful for the functionalization of pyrazine ring.
作者:Shlomy Arava、Jayprakash N. Kumar、Shimon Maksymenko、Mark A. Iron、Keshaba N. Parida、Peter Fristrup、Alex M. Szpilman
DOI:10.1002/anie.201610274
日期:2017.3.1
Enolonium species/iodo(III)enolates of carbonyl compounds have been suggested to be intermediates in a wide variety of hypervalent iodine induced chemical transformations of ketones, including α‐C−O, α‐C−N, α‐C−C, and α‐carbon–halide bond formation, but they have never been characterized. We report that these elusive umpoled enolates may be made as discrete species that are stable for several minutes
Evaluation of β- and γ-Effects of Group 14 Elements Using Intramolecular Competition
作者:Masanobu Sugawara、Jun-ichi Yoshida
DOI:10.1021/jo991977t
日期:2000.5.1
gamma-elimination of tin is faster than the beta-elimination of silicon, but slower than the beta-elimination of germanium and tin. The theoretical studies using ab initio molecular orbital calculations of the carbocation intermediates are consistent with the experimental results. The effect of substituents on silicon was also studied. The introduction of sterically demanding substituents on silicon disfavored