Regioselective Aminobromination of Terminal Alkenes.

Abstract

Addition reactions Addition reactions O 0060Regioselective Aminobromination of Terminal Alkenes. -Several N-Boc-2-bromoamines are prepared by a two-step method involving the reaction of new dibromocarbamate (II) with terminal alkenes to give N-bromo-N-Boc adducts, which are reduced in situ. Deprotection of these N-Boc products by treatment with HCl or TosOH affords the corresponding ammonium salts in pure state and good overall yields. The observed regioselectivity of the aminobromination for anti-Markovnikov addition is fully consistent with the radical-chain mechanism proposed for the reaction. -(SLIWINSKA, A.; ZWIERZAK*, A.; Tetrahedron 59 (2003) 31, 5927-5934; Inst. Org. Chem., Tech. Univ., PL-90-924 Lodz, Pol.; Eng.) -Klein 45-036

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

“…The same group again described the addition of BBC to several straight and branched chain terminal alkenes, namely, styrene, 2-phenylpropene, isobutylene, 2-methylbut-1-ene, 3methylbut-1-ene, pent-1ene, hex-1-ene, hept-1-ene, oct-1-ene, and 2,4,4-trimethylpent-1-ene. 1408 All reactions were carried out in refluxing dichloromethane by adding dropwise the solution of BBC to an equimolar amount of the alkene. They observed that the addition of BBC to styrene was disturbed by relatively fast consecutive cyclization of the primarily formed N-Boc-(2-bromo-2-phenylethyl)amine to 5-phenyloxazolidin-2-one (Scheme 517).…”

“…The same group again described the addition of BBC to several straight and branched chain terminal alkenes, namely, styrene, 2-phenylpropene, isobutylene, 2-methylbut-1-ene, 3-methylbut-1-ene, pent-1ene, hex-1-ene, hept-1-ene, oct-1-ene, and 2,4,4-trimethylpent-1-ene …”

Mitsunobu and Related Reactions: Advances and Applications

“…It is even possible to use a substrate such as HN(CO 2 Me)(Boc), HN(Cbz) 2 , or ethyl oxamate [EtO 2 CC(O)NHBoc] to prepare N -Boc amines (e.g. 337 ; Scheme ) in good yields after suitable deprotection. − The latter nucleophile EtO 2 CC(O)NHBoc has been obtained by starting with ethyl oxamate . The trityl group also activates nitrogen in aziridine formation from 1-amino-2-alcohols, as reported by Somfai and co-workers. , Kim and Kahn have performed the Mitsunobu N -alkylation of Boc-protected amino-oxazoles and -thiazoles with lysinol and argininol to obtain reduced peptidyl azoles .…”