import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  sampleObj = [
    {'checked': false, name: 'option 1'},
    {'checked': false, name: 'option 2'},
    {'checked': false, name: 'option 3'},
    {'checked': true, name: 'option 4'}
  ];

  sampleFunc(event, i) {
    if (event.currentTarget.checked) {
      alert(i);
      this.sampleObj[i].checked = false;
    }
  }
}

<div *ngFor="let item of sampleObj; let i = index">
  <input type='checkbox' name='item{{i}}' [(ngModel)]="item.checked" (change)="sampleFunc($event, i)" />
  <label for='item{{i}}'><span>{{item.name}}</span></label>

</div>

Angular CLI: 7.1.1
Node: 10.14.2
OS: win32 x64
Angular: 7.1.1
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, language-service, material, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.11.1
@angular-devkit/build-angular     0.12.1
@angular-devkit/build-optimizer   0.12.1
@angular-devkit/build-webpack     0.12.1
@angular-devkit/core              7.1.1
@angular-devkit/schematics        7.1.1
@angular/pwa                      0.11.2
@angular/service-worker           7.1.2
@ngtools/webpack                  7.2.1
@schematics/angular               7.1.1
@schematics/update                0.11.1
rxjs                              6.3.3
typescript                        3.1.6
webpack                           4.23.1