Palladium-catalyzed additions of silyl-element bonds to bicyclopropylidene-A new access to bicyclopropyl and functionally substituted cyclopropylidenepropane derivatives.

Palladium-catalyzed additions of disilanes, silylboranes, silylstannanes, and silyl cyanides across the double bond of bicyclopropylidene proceed with remarkable ease by two modes yielding either bicyclopropyl or cyclopropylidenepropane derivatives.

Fischer Carbene Complexes as Chemical Multitalents: The Incredible Range of Products from Carbenepentacarbonylmetal alpha,beta-Unsaturated Complexes.

The metal carbene complexes, discovered by E. O. Fischer at the start of the 1960s and carrying his name, have since proved themselves to be irreplaceable building blocks for organic synthesis.

Regioselective synthesis of medium-sized bicyclic butenolides by lewis acid catalyzed cyclization of cyclic 1, 3-Bis(trimethylsilyloxy)-1,3-butadienes with oxalyl chloride.

A new strategy for the synthesis of medium-sized bicyclic gamma-alkylidenebutenolides is reported which involves Me(3)SiOTf-catalyzed cyclization of cyclic 1, 3-bis(trimethylsilyloxy)-1,3-butadienes with oxalyl chloride.

Domino reaction of 1,3-bis(trimethylsilyloxy)-1,3-dienes with oxalyl chloride: general and stereoselective synthesis of gamma-alkylidenebutenolides.

The Lewis acid catalyzed cyclization of oxalyl chloride with 1,3-bis(trimethylsilyloxy)-1,3-dienes 3, derived from 1,3-dicarbonyl compounds 1, provides a new and general approach for the synthesis of gamma-alkylidenebutenolides 4, a pharmacologically and synthetically important class of substances. A variety of butenolides were efficiently prepared in good yields and with very good regio- and stereoselectivities. An up-scaling of the reaction was possible.

Efficient synthesis of butenolide-medium ring ether hybrids by a [3 + 2] cyclization-ring-closing metathesis strategy.

A new strategy for the synthesis of bicyclic gamma-alkylidenebutenolides, butenolide-medium ring ether hybrids, is reported which involves Me(3)SiOTf-catalyzed cyclization of 1, 3-bis(trimethylsilyloxy)-1,3-butadienes with oxalyl chloride, Mitsunobu reaction, and subsequent ring-closing metathesis.

Stereoselective synthesis of 2-alkylidene-3-iminoindoles by reaction of 1,1-dianions with oxalic acid bis(imidoyl) chlorides.

Treatment of dilithiated nitriles and sulfones with oxalic acid bis(imidoyl) chlorides resulted in a new cyclization reaction which provided a variety of (3-imino-2, 3-dihydro-1H-indol-2-ylidene)acetonitriles and -sulfones in good yields. The reactions proceeded by condensation of the dianions with the first imidoyl chloride group of the bis(imidoyl) chloride, subsequent intramolecular attack of the ortho carbon of the arylimino group onto the second imidoyl chloride group, and final aromatization. Excellent stereoselectivities were observed in most cases.

First domino mukaiyama-aldol cyclizations of 1, 3-Bis(trimethylsiloxy)-1,3-butadienes with 1,2-diketones.

The first domino Mukaiyama-aldol cyclization of 1, 3-bis(trimethylsiloxy)-1,3-dienes with enolizable 1,2-diketones provides a convenient and regioselective access to substituted cyclopent-2-en-1-ones.

Thermal Rearrangement of Nitrone and Nitrile Oxide Cycloadducts to Bicyclopropylidene.(1) Synthesis of 3-Spirocyclopropane-4-pyridone and Furo[2,3-c]pyridine Derivatives.

Bicyclopropylidene smoothly undergoes 1,3-dipolar cycloadditions to nitrones or nitrile oxides under different reaction conditions. The strained bisspirocyclopropanated isoxazolidines obtained from nitrones easily rearrange upon heating with selective opening of one of the two spirofused cyclopropane rings. This process produces 4-pyridone, 7-indolizinone, and 2-quinolizinone derivatives containing a spirocyclopropane moiety in the alpha-position to the carbonyl group in good yields.