ISSN:
0009-2940
Keywords:
[2 + 1] Cycloadditions
;
Hydrogen cyanide
;
Phosphorus dipolarophiles
;
Three-membered rings
;
Calculations, ab initio
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
We performed a systematic investigation of [2 + 1] cycloadditions of HN≡C to dipolarophiles of the type CH2=X and PH=X with X=CH2, NH, O, SiH2, PH, and S, as well as HN=NH and H2Si=SiH2. Ab initio MO calculations at the QCISD(T)/6-311G(d,p)/MP2/6-31G(d,p)+ZPE level were applied to construct the minimum-energy reaction pathways. Calculated results concerning the regiochemistry of the approaches and the stereochemistry of the product formation were analyzed in relation with established concepts such as frontier orbital, net charge distribution and stereoelectronic effect. For some systems, up to four distinct transition structures for cycloaddition were found. In general, there is a certain similarity between the behavior of both C and P series of dipolarophiles. The characteristics of the transition structures can be, in most cases, recovered by using qualitative concepts. The [2 + 1] cycloadditions are highly regioselective and stereospecific. Silicon-containing dipolarophiles are particularly attractive as they exhibit very small energy barriers to addition to isocyanides.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19971300111
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