In Situ Generation and Intramolecular Schmidt Reaction of Keto Azides in a Microwave-Assisted Flow Format
作者:Thomas O. Painter、Paul D. Thornton、Mario Orestano、Conrad Santini、Michael G. Organ、Jeffrey Aubé
DOI:10.1002/chem.201100768
日期:2011.8.22
Go with the flow! A method for conversion of keto halides to lactams by means of sequential azidation and intramolecularSchmidtreaction in a combined flowformat is described (see scheme; MWI=microwave irradiation, TFA=trifluoroacetic acid).
A Schmidt route to 1-azabicyclo[x.y.0]alkanes: a comparison of carbocation stabilizing groups
作者:William H Pearson、Rajesh Walavalkar
DOI:10.1016/s0040-4020(01)00353-2
日期:2001.6
The intramolecular Schmidt reactions of tertiary alkyl, tertiarybenzylic, tertiary propargylic, and tertiary allylic carbocations with tethered azides are reported. Using product analysis and deuterium labeling studies, the role of cation rearrangement prior to Schmidt reaction is reported.
Sequenced reactions with samarium(II) iodide. Intermolecular ketyl-olefin coupling/intramolecular nucleophilic acyl substitution for the preparation of six-, seven-, and eight-membered carbocycles
作者:Gary A Molander、Masakazu Sono
DOI:10.1016/s0040-4020(98)00584-5
日期:1998.8
A samarium(II) iodide-promoted sequence consisting of an intermolecular ketyl-olefin coupling followed by an intramolecular nucleophilic acyl substitution is described. This process leads to functionalized six- to eight-membered monocyclic and bicyclic ring systems in moderate to good yields.
Intramolecular nucleophilic acyl substitution reactions of halo-substituted esters and lactones. New applications of organosamarium reagents
作者:Gary A. Molander、Jeffrey A. McKie
DOI:10.1021/jo00077a053
日期:1993.12
Intramolecular nucleophilic acyl substitution reactions involving a broad range of halo substituted carboxylic acid derivatives have been accomplished in excellent yield employing samarium(II) iodide as the reductive coupling agent. Although particular substrates cyclized most effectively in THF in the presence of tripiperidinophosphine oxide, carboxylic acid esters, the focus of this report, cyclize equally well without such an additive in the presence of a catalytic quantity of iron(III) complexes. Thus a comprehensive series of halo substituted esters were cyclized in excellent yield to the corresponding 4-, 5-, and 6-membered carbocycles. The reaction is extremely mild and selective as demonstrated by experiments wherein alkyl chlorides, acetals, and olefins remain completely intact under the reaction conditions. In addition to introducing a convenient procedure for preparing stereodefined spirocyclic systems, a new ring expansion sequence has been developed that appears extremely general for the preparation of various ring systems.
Sequenced Reactions with Samarium(II) Iodide. A Complementary Annulation Process Providing Access to Seven-, Eight-, and Nine-Membered Carbocycles
作者:Gary A. Molander、Fouzia Machrouhi
DOI:10.1021/jo990216n
日期:1999.5.1
Samarium(II) iodide promotes an efficient one-pot annulation reaction between omega-iodo esters and 2-(omega-chloroalkyl)cycloalkanones. An initial intermolecular carbonyl addition reaction between the iodo ester and the ketone generates a lactone intermediate. The lactone undergoes a subsequent nucleophilic acyl substitution reaction with an organosamarium derived from the chloride. Nickel(II) iodide is an efficient catalyst for the first step of the process, and light is utilized to promote the second step. Seven-, eight-, and nine-membered rings can be accessed by this sequential dianionic process. This annulative approach to carbocycles is complementary to previously reported procedures.