Crystallographic report: Trimethylaminedibromopropoxycarbonylborane

Abstract

The conformation around the boron atom is nearly tetrahedral, with Br-B-Br bond angles of 109.14(19) • COMMENTA new one-pot method for the synthesis of trimethylaminedibromocarboxyborane esters from trimethylaminecarboxyborane in high purity and excellent yields was reported previously.1 Since a boron-attached bromine atom is considered to be a good leaving group, 2 such compounds are considered as precursors for boron-substituted amine carboxyboranes, which are isoelectronic boron analogs of α-amino acids and their derivatives.3 In this connection, the molecular structure has been determined, Fig. 1. The conformation around the boron atom is nearly ideally tetrahedral, with Br-B-Br bond angles of 109.14(19)• and slightly wider N-B-C bond angles up to 113.6(3)• . The observed data are comparable to those found in related compounds that contain an N-BBr 2 -C fragment.4,5 EXPERIMENTALThe title compound was prepared from trimethylaminecarboxyborane in a one-pot method as described elsewhere.

Diborane (4) derivatives via coupling of amine monobromocyanoboranes: Study of the bromination of amine cyanoborane and molecular structures of the amine dibromocyanoboranes

“…Those of the N-BBr 2 -C"N are of a particular significance in the present context, and are summarized in Table 3. The observed data are comparable to those found in related compounds that contain the NBBr 2 -C fragment [31][32][33][34][35][36]. The conformation around the boron atom is nearly ideally tetrahedral, with Br-B-Br and N-B-C bond angles of 109°, and the conformation around the carbon atom in B-C"N moiety is nearly linear with B-C"N bond angles of 178.5°and 176.7°.…”