Alkyl-substituted alkynyl

When l-[o-(phenylethynyl)phenyl]cyclopropanol-Co2(CO)6 complex (36) is heated at 50 °C in 2-propanol under argon in the presence of DABCO, a completely different product, 3a,4-dihydro-3ff-cyclopenta[a]inden-2-one derivative 40, is produced as a 95 5 diastereomeric mixture in 72% yield. As shown in Scheme 18, not only aryl-substituted alkynyl derivatives, but also alkyl-substituted alkynyl derivatives, give the corresponding cyclopenta[a]inden-2-one derivatives 40 in moderate to good yields. 

Benzofulvenes have been prepared by [(IPrlAuNTfj] [IPr = l,3-bis(diisopropyl-phenyl)imidazolylidene]-catalysed cyclization of diynes with terminal alkynyl groups and t-alkyl-substituted alkynyl groups (Scheme 114). ... 

This chapter covers recent information on the preparation, physical properties, and reactions of quinoxaline and its C-alkyl, C-aryl, iV-alkyl, and A-aryl derivatives as well as their respective ring-reduced analogs. In addition, it includes methods for introducing alkyl or aryl groups (substituted or otherwise) into quinoxalines already bearing substituents and the reactions specific to the alkyl or aryl groups in such compounds. For simplicity, the term alkylquinoxaline in this chapter is intended to include alkyl-, alkenyl-, alkynyl-, and aralkylquinoxalines likewise, arylquino-xaline includes both aryl- and heteroarylquinoxalines. 

Pentacene is a useful compound in materials science, in particular for use in solar batteries, superconductors, and laser emission materials, etc. Unfortunately, however, pentacene is not soluble in organic solvents. As shown in Eq. 2.57, a combination of the aforementioned benzene formation reaction and alkynylation of phthalate leads to alkyl-substituted pentacenes, which are very soluble in various organic solvents... 

Addition to linear 1,1-disubstituted allylic acetates is slower than addition to monosubstituted allylic esters. Additions to allylic trifluoroacetates or phosphates are faster than additions to allylic carbonates or acetates, and reactions of branched allylic esters are faster than additions to linear allylic esters. Aryl-, vinyl, alkynyl, and alkyl-substituted allylic esters readily undergo allylic substitution. Amines and stabilized enolates both react with these electrophiles in the presence of the catalyst generated from an iridium precursor and triphenylphosphite. 

Secondary and tertiary dialkylcuprates, lithium dialkenyl-, and even diphenyl-cuprates, add in very good yields to the reactive propionaldehyde diethyl acetal. The syn addition products may be trapped with a variety of electrophiles such as alkyl, alkenyl, alkynyl and aryl halides. The method has been used for the synthesis of several natural products. Substituted alkynic acetals also react with lithium dialkylcuprates in ether to furnish stable dialkenylcuprates of type (128) which do not eliminate to the corresponding alkoxy allenes (129) if the temperature is maintained below -20 C.164-179... 

Hydrocarbons consist entirely of nonpolar C-H bonds with no unpaired electrons. These compounds are relatively unreactive. The substitution of one or more atoms with unpaired electrons into the hydrocarbon backbone creates a hydrocarbon derivative. The unpaired electrons result in polar or charged portions of these molecules. These atoms fall into categories known as functional groups, and they create local regions of reactivity. Alkyl, alkenyl, alkynyl, and aryl groups may also be considered functional groups in some circumstances as described in the previous skill. 

R = alkyl, substituted alkyl, alkenyl, alkynyl, benzyl... 

Cyclopentadienyl-substituted vanadium(III) compound (93) is also allowed to undergo the substitution reaction to give the a-alkyl, a-alkynyl, or a-aryl complexes (94, Scheme 52). 2,132-137 [nbu4][V(C6C15)4], which is prepared... 

Alkynyl ketones can be formed from addition of alkynyllithium or Grignard reagents to phthalimides and then the products converted into pyrazoles by reaction with hydrazines. For example, A -alkyl-substituted phthalimides 633 were easily transformed to mono-, di-, or trisubstituted pyrazoles 634 via a one-pot addition/decyclization/cyclocon-densation process (Equation 131) <2002J(P1)207>. A -Alkyl-substituted phthalimides 635 were easily converted into di-, tri-, and tetrasubstituted pyrazoles 636 via a one-pot addition-decyclization-cyclocondensation process (Equation 132) <2003H(60)2499>. 

Substituted 3-thiazolines (16) are stable and easily prepared, but are inert to organometallic addition. Activation of (16) with BF3-OEt2 followed by organometallic addition (R MgX, R Li) provides trans-4,S-disubstituted Aiazolidines (36) (masked 2-aminothiols) in which R = aryl, alkyl or alkynyl (equation... 

No general method is available for tert-alkyl-alkynyl-coupling based on sodium or lithium alkynylide reagents because of prevalent elimination. However, trialkyn-ylalanes obtained from the corresponding alkynyllithiums and anhydrous aluminum trichloride undergo clean reaction with tert-halides to produce rert-alkyl substituted... 

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