Reaction of allene esters with Selectfluor/TMSX (X = I, Br, Cl) and Selectfluor/NH₄SCN: Competing oxidative/electrophilic dihalogenation and nucleophilic/conjugate addition

• A. Srinivas Reddy and
• Kenneth K. Laali

Beilstein J. Org. Chem. 2015, 11, 1641–1648, doi:10.3762/bjoc.11.180

• Selectfluor and to promote dihalogenation, CuBr was used as an additive [16][17], but the outcome remained unchanged. In the absence of Selectfluor the same hydrohalogenation products 1c and 1d were isolated but in different ratios (Scheme 2). The reaction of benzyl allenoate (1) with TMSI in MeCN (Scheme 3

Polar reactions of acyclic conjugated bisallenes

• Reiner Stamm and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 36–48, doi:10.3762/bjoc.9.5

• and epoxides, hydrohalogenation (HCl, HBr addition), halogenation (Br2 and I2 addition), and [2 + 2] cycloaddition with chlorosulfonyl isocyanate. The resulting adducts were fully characterized by spectroscopic and analytical methods; they constitute interesting substrates for further organic

• transformations. Keywords: β-lactams; conjugated bisallenes; cyclopentenones; epoxidation; halogen addition; hydrohalogenation; ionic additions; metalation; Introduction Whereas the use of hexa-1,2,4,5-tetraene (1) and its derivatives in pericyclic reactions is well documented [2][3][4][5][6], relatively little

• . Hydrohalogenation and halogenation of acyclic conjugated bisallenes Hydrohalogenation of 2 and 5 The addition of protic acids HX (with X usually being Cl and Br) to allenes has been studied quite carefully. The process usually takes place according to the Markovnikoff rule and often cannot be stopped at the