50598-97-5

Upstream product

• 766-77-8 Dimethylphenylsilane 
• 36306-56-6 crotylmagnesium bromide 
• 3839-31-4 dimethyl(phenyl)silyllithium 
• 106-99-0 buta-1,3-diene 
• 6737-11-7 2-acetoxy-3-butene 
• 91076-08-3 bis(dimethylphenylsilyl)zinc 
• 18992-90-0 but-3-en-2-yl phenylcarbamate 
• 109790-06-9 (but-3-en-1-yl)dimethyl(phenyl)silane 
• 65001-62-9 3-buten-2-yl benzoate 
• 769-00-6 (iodomethyl)dimethylphenylsilane 
• 185027-04-7 1-dimethyl(phenyl)silylbut-2-yne 
• 104664-93-9 (Z)-crotyl benzoate 
• 21969-32-4 crotylmagnesium chloride 

Downstream Products

• 120196-08-9 4-dimethyl(phenyl)silylbutan-2-ol 
• 120196-09-0 1-Dimethyl(phenyl)silylbutan-2-ol 

Relevant academic research and scientific papers

Highly Z-Selective Double Bond Transposition in Simple Alkenes and Allylarenes through a Spin-Accelerated Allyl Mechanism

Double-bond transposition in alkenes (isomerization) offers opportunities for the synthesis of bioactive molecules, but requires high selectivity to avoid mixtures of products. Generation of Z-alkenes, which are present in many natural products and pharmaceuticals, is particularly challenging because it is usually less thermodynamically favorable than generation of the E isomers. We report a β-dialdiminate-supported, high-spin cobalt(I) complex that can convert terminal alkenes, including previously recalcitrant allylbenzenes, to Z-2-alkenes with unprecedentedly high regioselectivity and stereoselectivity. Deuterium labeling studies indicate that the catalyst operates through a π-allyl mechanism, which is different from the alkyl mechanism that is followed by other Z-selective catalysts. Computations indicate that the triplet cobalt(I) alkene complex undergoes a spin state change from the resting-state triplet to a singlet in the lowest-energy C-H activation transition state, which leads to the Z product. This suggests that this change in spin state enables the catalyst to differentiate the stereodefining barriers in this system, and more generally that spin-state changes may offer a route toward novel stereocontrol methods for first-row transition metals.

Silicon Grignard Reagents as Nucleophiles in Transition-Metal-Catalyzed Allylic Substitution

A broad range of transition-metal catalysts is shown to promote allylic substitution reactions of allylic electrophiles with silicon Grignard reagents. The procedure was further elaborated for CuI as catalyst. The regioselectively is independent of the leaving group for primary allylic precursors, favoring α over γ. The stereochemical course of this allylic transposition was probed with a cyclic system, and anti -dia-stereoselectivity was obtained.

An alternative mechanism for the cobalt-catalyzed isomerization of terminal alkenes to (Z)-2-alkenes

The cobalt-catalyzed selective isomerization of terminal alkenes to the thermodynamically less-stable (Z)-2-alkenes at ambient temperatures takes place by a new mechanism involving the transfer of a hydrogen atom from a Ph2PH ligand to the starting material and the formation of a phosphenium complex, which recycles the Ph2PH complex through a 1,2-H shift.

Double-Bond Isomerization: Highly Reactive Nickel Catalyst Applied in the Synthesis of the Pheromone (9 Z,12 Z)-Tetradeca-9,12-dienyl Acetate

A highly reactive nickel catalyst comprising NiCl2(dppp) or NiCl2(dppe) with zinc powder, ZnI2 and Ph2PH, was applied in the isomerization of terminal alkenes to Z-2-alkenes. The double-bond geometry of the 2-alkene can be controlled via the reaction temperature to yield the 2-Z-alkenes in excellent yields and high Z-selectivities. The formation of other constitutional isomers, such as 3-alkenes, is suppressed on the basis of the proposed mechanism via a 1,2-hydride shift from the metal to the Ph2P ligand. The nickel-catalyzed isomerization reaction was then applied in the synthesis of (9Z,12Z)-tetradeca-9,12-dienyl acetate, a pheromone with a 2Z,5Z-diene subunit.

Practical synthesis of allylic silanes from allylic esters and carbamates by stereoselective copper-catalyzed allylic substitution reactions

The first copper-catalyzed allylic substitution reactions of allylic acetates and carbamates employing a bis(triorganosilyl)zinc reagent are reported. This novel procedure avoids the use of stoichiometric amounts of copper salts which are usually mandatory with this chemistry. Application of this methodology to standard model substrates substantiates a high diastereoselectivity for the double bond geometry (E:Z) as well as the relative configuration (syn:anti).

Regioselective 1,4-silylcupration of 1,3-dienes - Characterization and electrophilic trapping of the intermediate σ-allyl)copper complex

Silylcupration reactions of 1,3-dienes with a cyanocuprate reagent PhMe2SiCuCNLi produce a (4-silyl-2-alken-1-yl)-copper complex, which was trapped by electrophiles. The use of allylic phosphates as electrophiles resulted in highly regioselecti

Manganese-Catalyzed Silylmagnesiation of Acetylenes and 1,3-Dienes

The treatment of 4-benzyloxy-1-butyne with PhMe2SiMgMe in the presence of a catalytic amount of MnCl2 gave a monosilylated product, (E)-PhCH2OCH2CH2CH=CHSiMe2Ph, selectively after an aqueou

The Regiochemistry and Stereochemistry of the Hydroboration of Allylsilanes

The hydroboration of a wide range of allylsilanes 3 and 5-21 is found to be generally regioselective for attachment of the boron to C-3 and hydrogen to C-2 of the allyl unit, and to be generally stereoselective in the sense 1, with attachment of the boron

A Regioselective and Stereospecific Synthesis of Allylsilanes from Secondary Allylic Alcohol Derivatives

Primary and secondary allylic acetates and benzoates react with the dimethyl(phenyl)silyl-cuprate reagent to give allylsilanes, provided that the THF in which the cuprate is prepared is diluted with ether before addition of the allylic ester.The reaction is reasonably regioselective in some cases: (i) when the allylic system is more-substituted at one end than the other, as in the reactions 4->5 and 9->10; (ii) when the steric hindrance at one end is neopentyl-like, as in the reactions 15->16; and (iii) when the disubstituted double bond has the Z configuration, as in th e reactions Z-19->E-21 or, better, because the silyl group is becoming attached to the less-sterically hindered end of the allylic system, Z-20->E-22.The regioselectivity is better if a phenyl carbamate is used in place of the ester, and a three-step protocol assembling the mixed cuprate on the leaving group is used, as in the reactions 23->24 and E- or Z-29->E-21, or, best of all, because the silyl group is again becoming attached to the less-sterically hindered end of the allylic system, E- or Z-30->E-22.This sequence works well to move the silyl group onto the more substituted end of an allyl system, but only when the move is from a secondary allylic carbamate to a tertiary allylsilane, as in the reaction 38->39.Allyl(trimethyl)silanes can be made using alkyl- or aryl-cuprates on trimethylsilyl-containing allylic esters and carbamates, as in the reactions 40->41, and 43->44.The reaction of the silyl-cuprate with allylic esters and the three-step sequence with the allylic carbamates are stereochemically complementary, the former being stereospecifically anti and the latter stereospecifically syn.Homochiral allylsilanes can be ma de by these methods with high levels of stereospecificity, as shown by the synthesis of the allylsilanes 54, 58 and 59.

SELECTIVE SYNTHESIS OF (E)-CROTYLSILANES BY REACTION OF CROTYLMAGNESIUM BROMIDE WITH HYDROSILANES IN THE PRESENCE OF DICHLORONIKKEL(II)

Dichloronickel(II) was found to be an effective catalyst for the reaction of crotylmagnesium bromide with hydrosilanes to give (E)-crotyl-silanes selectively.