4714-10-7

Upstream product

• 3416-63-5 4-trityl-1-(diphenylmethyl)benzene 
• 908094-04-2 phenyldiazomethane 
• 110-83-8 cyclohexene 
• 100-39-0 benzyl bromide 
• 87413-32-9 (cyclohex-2-enylsulfonyl)benzene 
• 630-76-2 tetraphenylmethane 
• 5281-18-5 benzaldehyde, hydrazone 
• 1165952-91-9 cyclohexa-1,3-diene 
• 1521-51-3 rac-3-bromocyclohexene 
• 87100-28-5 pinacol benzylboronate 
• 76644-52-5 rac-3-acetoxycyclohexene 
• 100-52-7 benzaldehyde 
• 12083-24-8 tricarbonyl(η(6)-toluene)chromium 
• 102147-31-9 tert-butyl cyclohex-2-enyl carbonate 

Relevant academic research and scientific papers

Transition Metal-Free sp3?sp3 Carbon-Carbon Coupling between Benzylboronic Esters and Alkyl Bromides

A transition metal-free coupling reaction of benzylboronic esters and alkyl halides has been developed. Both alkyl bromides and alkyl iodides were found to be competent substrates with the nucleophilic boronate intermediate generated from the combination of benzylboronic ester and an alkyllithium. Good chemoselectivity was observed for the reaction with the alkyl bromide in substrates with a second electrophile present. Both secondary and tertiary benzylboronic esters were effective nucleophiles in the reaction with primary alkyl halides. Mechanistic observations are consistent with a radical mechanism.

Nickel-Catalyzed Regioselective Hydrobenzylation of 1,3-Dienes with Hydrazones

Hydroalkylation of unsaturated hydrocarbons with unstabilized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far have mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydrobenzylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acting as both the sources of unstabilized carbanion equivalent and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.

Umpolung of Carbonyl Groups as Alkyl Organometallic Reagent Surrogates for Palladium-Catalyzed Allylic Alkylation

Palladium-catalyzed allylic alkylation of nonstabilized carbon nucleophiles is difficult and remains a major challenge. Reported here is a highly chemo- and regioselective direct palladium-catalyzed C-allylation of hydrazones, generated from carbonyls, as a source of umpolung unstabilized alkyl carbanions and surrogates of alkyl organometallic reagents. Contrary to classical allylation techniques, this umpolung reaction utilizes hydrazones prepared not only from aryl aldehydes but also from alkyl aldehydes and ketones as renewable feedstocks. This strategy complements the palladium-catalyzed coupling of unstabilized nucleophiles with allylic electrophiles by providing an efficient and selective catalytic alternative to the traditional use of highly reactive alkyl organometallic reagents.

Palladium-Catalyzed Electrochemical Allylic Alkylation between Alkyl and Allylic Halides in Aqueous Solution

A new route for the direct cross-coupling of alkyl and allylic halides using electrochemical technique has been developed in aqueous media under air. Catalyzed by Pd(OAc)2, the Zn-mediated allylic alkylations proceed smoothly between a full range of alkyl halides (primary, secondary, and tertiary) and substituted allylic halides. Protection-deprotection of acidic hydrogen in the substrates is avoided.

Raising the p K a Limit of soft nucleophiles in palladium-catalyzed allylic substitutions: Application of diarylmethane pronucleophiles

The Tsuji-Trost allylic substitution reaction provides a useful and efficient approach to construct C-C bonds between sp3-hybridized carbons. The widely accepted paradigm for classifying the mode of attack of nucleophiles on palladium π-allyl intermediates in the Tsuji-Trost reaction is based on the pKa of the pronucleophile: (1) stabilized or soft carbon nucleophiles and heteroatom nucleophiles (e.g., pronucleophiles with pKa's a's > 25). One of the keys to the continuing development of allylic substitution processes remains broadening the scope of soft nucleophiles. Herein we report a general method for the room temperature Pd-catalyzed allylic substitution with diarylmethane derivatives (pKa's up to 32). The synthetic significance of the method is that it provides a rapid access to products containing allylated diarylmethyl motifs. The method is general for a wide range of nucleophiles derived from diarylmethanes and heterocyclic derivatives. A procedure for the Pd-catalyzed allylic substitutions to afford diallylation products with quaternary centers is also described. With triarylmethanes and alkylated diarylmethanes the corresponding allylated products are isolated. We anticipate that the described method will be a valuable complement to the existing arsenal of nucleophiles in Pd-catalyzed allylic substitutions. Mechanistic studies show that the nucleophile derived from diphenylmethane undergoes external attack on π-allyl palladium species under our reaction conditions. This unexpected observation indicates that diarylmethane derivatives behave as soft or stabilized nucleophiles. The results of this study indicate that the cutoff between soft and hard nucleophiles should be raised from a pronucleophile pK a of 25 to at least 32.

Palladium-catalyzed allylic substitution with (η6-Arene- CH2Z)Cr(CO)3-based nucleophiles

Although the palladium-catalyzed Tsuji-Trost allylic substitution reaction has been intensively studied, there is a lack of general methods to employ simple benzylic nucleophiles. Such a method would facilitate access to "α-2-propenyl benzyl" motifs, which are common structural motifs in bioactive compounds and natural products. We report herein the palladium-catalyzed allylation reaction of toluene-derived pronucleophiles activated by tricarbonylchromium. A variety of cyclic and acyclic allylic electrophiles can be employed with in situ generated (η6-C 6H5CHLiR)Cr(CO)3 nucleophiles. Catalyst identification was performed by high throughput experimentation (HTE) and led to the Xantphos/palladium hit, which proved to be a general catalyst for this class of reactions. In addition to η6-toluene complexes, benzyl amine and ether derivatives (η6-C6H5CH 2Z)Cr(CO)3 (Z = NR2, OR) are also viable pronucleophiles, allowing C-C bond-formation α to heteroatoms with excellent yields. Finally, a tandem allylic substitution/demetalation procedure is described that affords the corresponding metal-free allylic substitution products. This method will be a valuable complement to the existing arsenal of nucleophiles with applications in allylic substitution reactions.

Decarboxylative allylation using sulfones as surrogates of alkanes

(Chemical Equation Presented) α-Sulfonyl functional groups are traceless activating groups that facilitate catalytic decarboxylative allylations in high yield yet can be cleaved to allow the synthesis of simple allylated alkanes. Substrate studies suggest

A chiral auxiliary cleavable by ring-closing alkene metathesis - Efficient synthesis of chiral nonracemic cycloalkenes

p-Menthane-3-carboxaldehyde is a readily available chiral auxiliary used to prepare cycloalkenes and heterocycles bearing a chiral tertiary or quaternary carbon of high enantiomeric purity. The auxiliary is available in both enantiomeric forms and is inexpensive and recyclable. It is cleaved by a ring-closing alkene metathesis reaction directly yielding the cycloalkene.

Integrated chemical process. Construction of highly substituted allylic moieties from allylic sulfones in one-pot

According to 'integrated chemical process', a novel one-pot process for construction of highly substituted allylic moieties has been achieved. A series of alkylation of allylic sulfones and palladium-catalyzed reductive desulfonylation by use of LiBHEt3 is integrated. The double alkylation furnishes more substituted olefins. Use of arylzinc compounds in place of the hydride enables electrophilic alkylation/nucleophilic arylation in one-pot. The integrated process provides higher overall yields than the corresponding stepwise process.

Free radical chemistry of β-lactones. Arrhenius parameters for the decarboxylative cleavage and ring expansion of 2-oxetanon-4-ylcarbinyl radicals. Facilitation of chain propagation by catalytic benzeneselenol

2-Oxetanon-4-ylcarbinyl radicals undergo facile ring opening with cleavage of the C-O bond to give 3-butenoxyl radicals which in turn suffer loss of carbon dioxide to provide allyl radicals. When the initial radical is generated from a bromolactone with Bu3SnH and AIBN, chain propagation is poor owing to the relatively slow abstraction of hydrogen from the stannane by the allyl radical. The inclusion of catalytic Ph2Se2, reduced in situ to PhSeH, provides for much smoother cleaner reactions because of the better hydrogen donating capacity of the selenol. The oxetanon-4-ylcarbinyl radical derived from 6-benzyl-1-(bromomethyl)-8-oxa-7-oxobicyclo[4.2.0]octane is anomalous and undergoes a radical ring expansion in competition with the fragmentation process. Possible reasons for this anomaly are presented as are Arrhenius functions for the fragmentation and rearrangement. The Arrhenius function for the fragmentation of a simple 2-oxetanon-4-yl radical is also presented. Conditions are described under which the fragmentation of 2- oxetanon-4-yl radicals may be suppressed.