Efficient Formal Total Synthesis of the Erythrina Alkaloid (+)-Erysotramidine, Using a Domino Process

A domino process consisting of an amidation, spirocyclization, and formation of an iminium ion and electrophilic aromatic substitution of a phenylethylamine and a ketoester leads to the spirocyclic skeleton of (+)-erysotramidine, which can be further transformed into the natural alkaloid

Efficient Formal Total Synthesis of the Erythrina Alkaloid (+)-Erysotramidine, Using a Domino Process

A domino process consisting of an amidation, spirocyclization, and formation of an iminium ion and electrophilic aromatic substitution of a phenylethylamine and a ketoester leads to the spirocyclic skeleton of (+)-erysotramidine, which can be further transformed into the natural alkaloid

A Ridge Walk between Reaction Modes: An Unprecedented Pd-Catalyzed Domino Sequence of Diynyl-Substituted Bromoarenes

Diynyl-substituted bromoarenes underwent a novel Pd-catalyzed domino reaction to provide benzofurans, pyridinofurans, isochromenes, and indole derivatives. Slight changes of the substrate push the reaction in another direction resulting in benzene annulation

Efficient Formal Total Synthesis of the Erythrina Alkaloid (+)-Erysotramidine, Using a Domino Process

A domino process consisting of an amidation, spirocyclization, and formation of an iminium ion and electrophilic aromatic substitution of a phenylethylamine and a ketoester leads to the spirocyclic skeleton of (+)-erysotramidine, which can be further transformed into the natural alkaloid

Reactivity Studies of a Ge^I−Ge^I Compound with and without Cleavage of the Ge−Ge Bond

This Communication describes two strikingly different reactivities of a digermylene [{PhC(NtBu)2}2Ge2] (1) featuring a GeI−GeI single bond. In the reaction with azobenzene, 1 affords the oxidative addition product LGeN(Ph)N(Ph)GeL [2; L = PhC(NtBu)2], with simultaneous cleavage of the Ge−Ge bond, whereas treatment of 1 with Fe2(CO)9 yields the Lewis acid−base adduct LGe[Fe(CO)4]Ge[(Fe(CO)4]L (3). Both compounds were characterized by single-crystal X-ray diffraction, NMR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis

Reactivity Studies of a Ge^I−Ge^I Compound with and without Cleavage of the Ge−Ge Bond

This Communication describes two strikingly different reactivities of a digermylene [{PhC(NtBu)2}2Ge2] (1) featuring a GeI−GeI single bond. In the reaction with azobenzene, 1 affords the oxidative addition product LGeN(Ph)N(Ph)GeL [2; L = PhC(NtBu)2], with simultaneous cleavage of the Ge−Ge bond, whereas treatment of 1 with Fe2(CO)9 yields the Lewis acid−base adduct LGe[Fe(CO)4]Ge[(Fe(CO)4]L (3). Both compounds were characterized by single-crystal X-ray diffraction, NMR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis

A Remarkable End-On Activation of Diazoalkane and Cleavage of Both C–Cl Bonds of Dichloromethane with a Silylene to a Single Product with Five-Coordinate Silicon Atoms

The 1:1 reaction of benzamidinato-stabilized chlorosilylene PhC­(N<i>t</i>Bu)₂SiCl (<b>1</b>) with CH­(SiMe₃)­N₂ resulted in the formation of colorless [PhC­(N<i>t</i>Bu)₂Si­(Cl)­{N₂CH­(SiMe₃)}]₂ (<b>2</b>), which consists of a four-membered Si₂N₂ ring. Surprisingly, N₂ elimination from the diazoalkane did not occur, but rather an end-on activation of the nitrogen was observed. For the mechanism, we propose the formation of a silaimine complex <b>A</b> as an intermediate, which is formed during the reaction and dimerized under [2 + 2] cycloaddition to <b>2</b>. In contrast, treatment of <b>1</b> with dichloromethane afforded a 2:1 product, [{PhC­(N<i>t</i>Bu)₂Si­(Cl₂)}₂CH₂] (<b>3</b>), which is obviously formed by oxidative addition under cleavage of both C–Cl bonds and formation of two Si–Cl and two Si–C bonds. Both silicon atoms in <b>3</b> are five-coordinate. Compounds <b>2</b> and <b>3</b> were characterized by single-crystal X-ray studies, multinuclear NMR spectroscopy, and EI-mass spectrometry

Synthesis and Structure of [{PhC(N<i>t</i>Bu)₂}₂Ge₂(μ-S)₂Cl₂] and a Germanium Dithiocarboxylate Analogue

LGeCl (L = PhC(NtBu)2) was treated with elemental sulfur in THF to afford [{PhC(NtBu)2}2Ge2(μ-S)2Cl2] (2) in 44% yield instead of yielding a compound containing a GeS double bond. It was revealed by the X-ray single-crystal structure that there is no GeS unit in 2. Instead, 2 features a four-membered ring containing two germanium and two sulfur atoms. The four-membered Ge2S2 ring is planar and is formed by a weak [2 + 2] cycloaddition interaction. Within the ring skeleton the two germanium atoms are arranged opposite to each other. Furthermore, 2 was reduced with 2 equiv of potassium graphite in THF to yield a potassium salt of a germathiocarboxylate analogue of composition [{PhC(NtBu)2}Ge(S)SK(THF)]2 (3). Compounds 2 and 3 were characterized by single-crystal X-ray diffraction studies, NMR spectroscopy, EI-MS spectrometry, and elemental analysis

One Pot Synthesis of Disilatricycloheptene Analogue and Jutzi’s Disilene

The reaction of LiN(TMS)2 (TMS = Me3Si) with dichlorosilane (Me5C5)SiHCl2 (1) in a molar ratio of 3:2 at ambient temperature leads to the formation of the disilatricycloheptene analogue (2). Compound 2 consists of three (three-, four-, and five-membered) fused rings that together form a six-membered heterocyclic ring. However, the reaction of 1 with KN(TMS)2 affords the formation of disilene of composition E-[(TMS)2N](η1-Me5C5)SiSi(η1-Me5C5)[N(TMS)2] (3) in good yield. This is a convenient and facile route for the synthesis of 3 in a single step and supports the formation of (Me5C5)SiN(TMS)2 as an intermediate

Donor-Substituted Nitrocyclopropanes: Immediate Ring-Enlargement to Cyclic Nitronates

The reaction of donor-substituted alkenes with α-diazo-α-nitro ethyl acetate under Rh catalysis was investigated; respective nitrocyclopropanes with a geminal ester functionality were generated in situ. Strong electron donors immediately led to ring-enlargement. In all cases, the nitro group was inserted forming cyclic nitronates whereas the ester moiety was not incorporated into the ring system. DFT studies revealed that the formation of cyclic nitronates is kinetically as well as thermodynamically favored over the formation of cyclic ketene acetals