Academic literature on the topic 'Organic compounds Cyclopropane'

Karl A. Scheidt of Northwestern University described (Organic Lett. 2009, 11, 1651) the oxidation of primary alcohols such as 1 in the presence of an indole 2. The product 3, an active acylating agent, is readily converted to other esters and amides. K. Rajender Reddy of the Indian Institute of Chemical Technology, Hyderabad, developed (Tetrahedron Lett. 2009, 50, 2050) a protocol for the direct oxidation of a primary amine 4 to the corresponding nitrile 5. In the presence of ammonia, the same procedure converted aldehydes and primary alcohols into the nitriles. Several catalytic methods for the oxidation of alcohols to aldehydes and ketones have recently been put forward. René Grée of the Université de Rennes 1 found ( Tetrahedron Lett. 2009, 50, 1493) that ZnBr2 catalyzed the oxidation of alcohols with diethyl azodicarboxylate. Tsutomu Katsuki of Kyushu University designed (Tetrahedron Lett. 2009, 50, 3432) a Ru catalyst for the air oxidation of primary alcohols to aldehydes. Kazuaki Ishihara of Nagoya University showed (J. Am. Chem. Soc. 2009, 131, 251) that 1 mol % of 10 was sufficient to catalyze the oxidation of 6 to 7. With excess oxidant, 7 was carried on cleanly to 11. Nitroxyl radicals such as TEMPO have long been used to catalyze oxidations. Yoshiharu Iwabuchi of Tohoku University developed (J. Org. Chem. 2009, 74, 4619) a simple preparation of 13 , the most efficient such catalyst reported so far. This catalyst should also be useful for the oxidation reported by Professor Iwabuchi (Chem. Commun. 2009, 1739) of primary alcohols and aldehydes to the corresponding carboxylic acids. David S. Forbes of the University of South Alabama prepared (Tetrahedron Lett. 2009, 50, 1855) 16 by combining thioanisole with N-bromosuccinimide. The reagent 16 efficiently sulfenylated active methylene compounds. Jiri Srogl of the Academy of Sciences of the Czech Republic established (Organic Lett. 2009, 11, 843) conditions for the oxidation of primary and secondary amines to aldehydes and ketones. Olga A. Ivanova of Moscow State University demonstrated (Tetrahedron Lett. 2009, 50, 2793) that DMDO 21 could oxidize a sensitive amino cyclopropane such as 20 to the corresponding nitro compound.

Nigel S. Simpkins, now at the University of Birmingham, found (Chem. Commun. 2008, 5390) that the prochiral cyclopropane amide 1 could be deprotonated to give, after alkylation, the substituted cyclopropane 3 with high enanantio- and diastereocontrol. In the course of a synthesis of (+)-Lineatin, Ramon Alibés of the Universitat Autònoma de Barcelona optimized (J. Org. Chem. 2008, 73, 5944) the photochemical cycloaddition of 4 and 5 to give, after reductive dechlorination, the cyclobutene 6. In a related reaction, José L. García Ruano and M. Rosario Martín of the Universidad Autónoma de Madrid observed (J. Org. Chem. 2008, 73, 9366) that the cycloaddition of 8 to 7 proceeded with high regio- and diastereocontrol, to give the cyclopentene 9. Joseph M. Ready of UT Southwestern in Dallas developed (Angew. Chem. Int. Ed. 2008, 47, 7068) a powerful new cyclopentannulation, condensing the cyclopropane derived from the addition of 11 to 10 with the protected ynolate 12 to give 13, in the presence of a modified Lewis acid catalyst. Chun-Chen Liao of the National Tsing Hua University, Hsinchu described (Angew. Chem. Int. Ed. 2008, 47, 7325) the oxidative ring contraction of the o-alkoxy phenol 14 to the cyclopentenone 15. Stéphane Quideau of the Université de Bordeaux reported (Organic Lett. 2008, 10, 5211) a related ring contraction. We uncovered (J. Org. Chem. 2008, 73, 9479) a simple protocol for the in situ conversion of an ω-alkenyl ketone such as 16 to the corresponding diazo compound, leading, via dipolar cycloaddition, to the adduct 17. Ulrich Zutter of Roche Basel described (J. Org. Chem. 2008 , 73, 4895), in a synthesis of Tamiflu, the hydrogenation of 19 to give the cyclohexane with all-cis diastereocontrol. Selective removal of the methyl ethers with trimethylsilyl iodide set the stage for enzymatic ester hydrolysis, delivering 20 in high ee.

Rubén Vicente and Luis A. López at the University of Oviedo in Spain reported (Angew. Chem. Int. Ed. 2012, 51, 8063) the synthesis of cyclopropyl furan 2 from alkylidene 1 and styrene by way of a zinc carbene intermediate. The same substrate 1 was also converted (Angew. Chem. Int. Ed. 2012, 51, 12128) to furan 3 via catalysis with tetrahydrothiophene in the presence of benzoic acid by J. Stephen Clark at the University of Glasgow. Xue-Long Hou at the Shanghai Institute of Organic Chemistry discovered (Org. Lett. 2012, 14, 5756) that palladacycle 6 catalyzes the conversion of bicyclic alkene 4 and alkynone 5 to furan 7. A silver-mediated C–H/C–H functionalization strategy for the synthesis of furan 9 from alkyne 8 and ethyl acetoacetate was developed (J. Am. Chem. Soc. 2012, 134, 5766) by Aiwen Lei at Wuhan University. Ning Jiao at Peking University and East China Normal University found (Org. Lett. 2012, 14, 4926) that azide 10 and aldehyde 11 could be converted to either pyrrole 12 or 13 with complete regiocontrol by judicious choice of a metal catalyst. Meanwhile, Michael A. Kerr at the University of Western Ontario developed (Angew. Chem. Int. Ed. 2012, 51, 11088) a multicomponent synthesis of pyrrole 16 involving the merger of nitrone 14 and the donor–acceptor cyclopropane 15. The pyrrole 16 was subsequently converted to an intermediate in the synthesis of the cholesterol-lowering drug compound Lipitor. A robust synthesis of the ynone trifluoroboronate 17 was developed (Org. Lett. 2012, 14, 5354) by James D. Kirkham and Joseph P.A. Harrity at the University of Sheffield, which thus allowed for the ready production of trifluoroboronate-substituted pyrazole 18. An alternative pyrazole synthesis via oxidative closure of unsaturated hydrazine 19 to produce 20 was reported (Org. Lett. 2012, 14, 5030) by Yu Rao at Tsinghua University. A unique fluoropyrazole construction was developed (Angew. Chem. Int. Ed. 2012, 51, 12059) by Junji Ichikawa at the University of Tsukuba that involved nucleophilic substitution of two of the fluorides in 21 to form pyrazole 22.