Neue Phospha- und Arsa-Heterocyclen aus Cyclophosphanen bzw. -arsanen (ECF₃)_n (E = P, As; n = 4, 5) und 1,3-Dienen / Novel Phospha- and Arsa-Heterocycles from Cyclophosphanes or -arsanes (ECF₃)_n (E = P, As; n = 4, 5) and 1,3-Dienes

Abstract

Neue Phospha-und Arsa-Heterocyclen aus Cyclophosphanen bzw. -arsanen (ECF3)" (E = P, As; n = 4, 5) und 1,3-Dienen Novel Phospha-and Arsa-Heterocycles from Cyclophosphanes or -arsanes (ECF3)" (E = P, As; n = 4, 5) and 1,3-Dienes Andreas Karst, Burkhardt Broschk, Joseph Grobe*, Duc Le Van

C–H Activation of Cycloalkenes by Dimetallynes (M = Ge, Sn) under Ambient Conditions

“…The reduction of CpH (BDE = 81.2 ± 2 kcal mol –1 , p K a = 18) under ambient conditions to give the aromatic Cp anion and H 2 is known only for highly reducing species: alkali metals, calcium metal, , metal carbonyls and low-valent f-element compounds . In contrast to these relatively harsh conditions, the Diels–Alder [4+2] cycloaddition between CpH and π-bonded species (e.g., alkenes, alkynes, disilenes, diphosphenes, diarsenes) is particularly facile due to the rigid cisoid conformation. Triply bonded dimetallynes are known to behave as dienophiles in Diels–Alder reactions. , It is therefore surprising to find that 1 and 2 do not react in such a manner and instead act as two-electron reducing agents toward two molecules of CpH.…”

Hydrostannylation of phosphaalkenes [1]

“…characteristic for 1,3-diphosphetanes [16,17]. The occurrence of two signals can be attributed to different stereoisomers of the 1,3-diphosphetane system, but an assignment of the signals to specific diastereomers is not possible.…”

Synthesis of distibiranes and azadistibiranes by cycloaddition reactions of distibenes with diazomethanes and azides

“… 5 Their formation can be rationalized by [2 + 2] cycloaddition of transient dipnictenes, however, the reaction of isolated dipnictene to cyclotetrapnictanes was not yet reported. Diels–Alder-type cycloaddition reactions were only reported for trapped (transient) diarsenes containing sterically less demanding substituents, 6 e.g . 2,3-bistrifluoromethyl-2,3-arsabicyclo[2.2.2]oct-5-ene was formed in a trapping reaction of in situ formed [CF 3 As] 2 with cyclohexadiene.…”